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There is little doubt but that Schmidt's Zones, 1, 2, 3 are the equivalents of all the North American rocks from the base of the Chazy limestone to the top of the Hudson River. Schmidt, Eichwald and others have lately greatly added to the number of species in these rocks. In the lists of fossils given by Schmidt in the work cited there are thirty-one species recognized as occurring in the Lower Silurian of America from the Chazy upwards. None of them occur below the Vaginatenkalk in Russia, and none of them below the Chazy in America. In Ehstland the Cystidean Sphæronites Leuchtenbergii or S. pomum occurs in (1). Echinosphærites aurantium in (1), and E. aranea in (1). These represent the American Chazy genera Malocystites and Palæocystites. The genus Bolboporites is confined to (1) in Ehstland and to the Chazy in Canada. The genus Illonus is most abundant in both countries in the same formations. Of the two Russian species of Maclurea, one is found in (1) and the other in (2, a). Ecculiomphalus Scoticus occurs in (1), and E. septiferus in (1, a)

The Orthoceratites, with large lateral siphuncles, also abound more in the base of the Russian limestones than in the upper strata. Taking all these facts together it seems highly probable that Schmidt's No. 1 represents the Chazy and Black River of North America.

The "Chloritische Kalk," or Chloritic limestone, seems to represent the Calciferous sandrock in part. This rock consists of a calcareous sandstone, with green grains and small globular

concretions. In some localities such as at Reval, Pöddis, Chudleigh, and Narwa, it becomes a magnesian limestone.

In lithological characters it therefore resembles the Calciferous sandrock, which, in the western or undisturbed portion of Canada, abounds in magnesian strata; and in the eastern, where it is expanded to a great thickness by the addition of slates and sandstones holds much chlorite where partially metamorphosed. The fossils cited by Schmidt are Orthis calligramma, O. extensa, O. parva, O. obtusa, Orthisina plana, Rhynconella nucella, and fragments of trilobites of the genera Illænus and Asaphus. In the limestones of Point Levi and Phillipsburgh we have three species scarcely distinguishable from O. parva, O. obtusa, and O. plana. So far as we can judge from external characters R. nucella is a Camerella, differing from C. calcifera in having the beaks closely incurved. The aspect of the Calciferous Brachiopods, so far as they are known, is more like that of the same group of fossils in the Chloritic limestone of Russia than that of any other formation.

The THONSCHIEFER or clay slate lying next below the Chloritic limestone is for us a most interesting formation, as it proves that in Russia there is (in or near the horizon of the Calciferous Sandrock) a ZONE OF GRAPTOLITES. It is described as a bituminous clay-slate, or alum-slate, with no fossils except traces of Obolus and an abundance of graptolites. Of these latter Schmidt identifies the following:

Graptolithus Sedgewickii. (Portlock.)

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Dictyonema flabelliformis. (Eichwald.)

It is not easy to identify species of graptolites, but with respect to the above it should be borne in mind that G. serratulus is a remarkable form consisting of two stipes diverging at an obtuse angle; and so Schmidt describes the Russian specimens. In New York it occurs at Norman's kill, associated with another species of the same type G. divaricatus. (Hall.) Schmidt may be wrong as to the perfect identity of the species, but his description shows clearly that his specimens must belong to the same group of graptolites. G. Sedgewickii is found in Dumfrieshire in Scotland in the Lower Llandeilo slates, far below the horizon of the Hudson River Group.D. flabelliformis very closely resembles a Quebec species. Setting aside all questions as to the identity of the species, it is an interesting fact that a naturalist in Russia should find below rocks which represent the limestones of the upper half of the Champlain group, a

slate full of graptolites, at the same time, that evidence is accumulating in Canada, which tends to prove the existence of graptolitic slates associated with the Calciferous Sandrock.

On comparing the Lower Silurian of England with that of America, it is found difficult to point out in the vast column of the British strata, the horizon representing the base of the limestones of the Champlain group. All that can be said on this question is, that there are about twenty species of fossils common to the Lower Silurian of the two countries, and that they all occur in England in the upper half of the Llandeilo and in the Bala group. None of them are found in the lower half. The place of the Calciferous Sandrock would appear thus to be about half way down the immense depth of the Llandeilo formation. But graptolites are found far below this level in England. The Skiddaw slates for instance are described by Prof. Sedgewick, as, "A group of vast thickness, and probably admitting of several subdivisions. In some of its upper beds a few graptolites and fucoids have been found. Generally it is without a trace of fossils. It is the supposed equivalent of the Longmynd Slate, (1a) of the Cambrian series. These slates appear thus to be of the age of the Lower Llandeilo. Yet they hold the following species of graptolites.

G. sagitarius. (Hisimger.)
G. tenuis. (Portlock.)

G. latus. (Mr. Coy.)

Associated with these are compound graptolites allied to species found at Quebec.† According to Prof Hall, G. sagitarius and G. tenuis are found at Norman's kill along with G. serratulus in slates which he considers to belong to the Hudson River group. I fancy that no British Geologist would think of placing the Skiddaw slates at the top of the Lower Silurian.

Again in the lowest slates of the Llandeilo, near the Stiper Stones in Shropshire G. geminus, G. pristis, and G. Murchisonii occur associated with Theca simplex (Salter), a species scarcely distinguishable from a Theca of which I have specimens from the Dikellocephalus sandstone of Wisconsin. These slates belong to the very base of the Lower Silurian, and repose upon the Lingula

British Palæozoic Fossils. Intr. p. xxi.

See SALTER'S note "On new fossils from the Skiddaw Slates." Geologist, Vol. 4., p. 74.

348 E. Billings on the Graptolites of the Lower Silurian.

Flags at the Stiper Stones, the true Primordial Zone as recognized in England. G. geminus as I understand occurs in Sweden in the upper part of the Lower Silurian. G. pristis ranges through the whole formation in different countries, and I believe that G. Murchisonii has a similar extended vertical distribution. A species occurs in the slates of the Quebec group which is clearly allied if not identical with G. geminus. On comparing the works of the different authors it will be seen that other species are identified as having not only a great geological but a wide geographical range. It would appear thus that graptolites cannot always be relied upon to show that exposures of rock widely separated from each other are either of a different or of the same age. In the Primordial Zone of Bohemia no graptolites have been discovered. Of the genus Dictyonema one species D. sociale (Salter) occurs in the Lingula Flags in England, but none of the ordinary graptolites have (unless very recently) been observed in that formation. In Sweden Dictyonema flabelliformis and a graptolite which Barrande says has " an appearance analogous to that of G. pristis" occurs in the slates of Andrarum, in Angelins REGIO B. in the true Primordial Zone. It would appear from all this that graptolites are rare in the Primordial Zone and that they abound in every stage of the second Fauna being most numerous in slaty rocks and rare in limestones and sandstones.†

As to their value in identifying strata Barrande observes that as "in general they consist of forms very similar in appearance it is difficult to distinguish them especially when found in fragments. The study of the family is not sufficiently advanced to enable us to recognise with certainty among its types those which may characterise exclusively each one of the three fauna of the Silurian."‡

I have prepared the above observations in order to show that the occurrence of graptolites in rocks so ancient as those of the Quebec group is not inconsistent with what we know of their geological range in other countries and consequently that we are not compelled to refer all the slates in which they are found in North America to the Hudson River group.

See Sir R. I. Murchison's 3rd Ed. of Siluria, pp. 39. 50.

† See BARRANDE's Parallèle entre les dépôts Siluriens de Scandinavie et de Bohème, p. 44. And also ANGELINS "Paleontologia Scandinavica,” P. IV.

Documens anciens et nouveaux sur la fauna primordiale et le système Taconique en Amérique, par M. J. Barrande, Bul. Geo. Soc. France. 20 Series, Vol. 18, p. 288.

ARTICLE XXVI.-A short review of the Sylviada or WoodWarblers found in the vicinity of Montreal. By H. G. VENNOR. (Presented to the Montreal Natural History Society)

Among the many families of birds visiting us during the summer months, and enlivening our woods and orchards with their songs, none are more interesting, agreeable, or. useful than the subjects of our present review. Excepting the humming-bird, we find among them the most diminutive of the feathered tribes. Yet, small and insignificant as these tribes may seem to be, they are designed by Providence to fill an important sphere in Nature. If it were possible to strike them off the list, and to leave their post vacant, we would soon find out to our loss that a great blank existed. The chorus of our woods would have lost its charm, and would resemble a grand piece of music, with the lower-toned, and connecting notes taken away. Thus leaving disconnected strains, truly beautiful and sweet in themselves, but, by being disconnected, having lost their charm.

Who can stroll through our woods during spring without being struck by the grand chorus produced by many sweet-noted songsters? But, let him analyze this swelling chorus, and it will be found that the sweet warble of the tiny warblers connecting the rich notes of the tanager, red-bird, thrush, and robin, forms the gentle swell that is so pleasing. This, however, would only be a mere loss of music; worse effects would follow. Soon our groves and forests would have lost their green fresh looks, and our orchards would have ceased to bear fruit ; and for this reasonthere exist around all vegetation hosts of minute insects that, left unmolested, would soon spread devastation through the vegetable kingdom. Myriads of these insects fall a prey to the thrushes, flycatchers, and swallows, but myriads more lurk and lie concealed beneath the bark, and under the leaves of the trees where neither thrush nor flycatcher could reach them. To this post, or sphere of usefulness, the true warblers are confined. With their bills they probe every crack and crevice of the bark, with their quick eye they glance over and under every leaf.

Think of the amount of good accomplished by even one of these birds in the capture of a parent insect, ready to deposit its eggs; it at least equals the destruction of a thousand caterpillars. The following is the general form of bill :-Slender, straight, and awl shaped; higher than wide at the base, and furnished with bristles; lower mandible straight. It is curious to watch some of

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