458 PROCEEDINGS OF TFIE NEW YORK MEETING 



thin bedded shales and limestones containing an interesting fauna, whicli seems 

 to be transitionaiy between tlie Trenton and Utica formations, and also to com- 

 mingle the fossil forms of the New .York Trenton with those of the Canadian for- 

 mations described by Billings. 



The outcrops along the eastern shore occur on successive promontories which 

 seem to be the result of a series of plications of the strata which curve on one side 

 and on the outer side have fractured witli more or less sharp faults. The beds 

 dilTer greatly in hardness, and both differeiitial erosion and differential shearing 

 are seen in them in consequence. 



Owing to the great variation of the dips and strikes following the plications of 

 the strata, and owing also to the numerous faults, all of which have been followed 

 out and plotted on the map, which will appear in the full report, it is yet impossible 

 to arrive at the exact thickness and relations of these beds. On the northeastern 

 side of Cumberland head a long, unfaulted, although considerably metamorphosed, 

 continuous section occurs, which measures 407 feet in thickness, but this seems to 

 be but the upper portion of the series. The latter series of beds reappears on Grand 

 isle, exactly opposite this locality, but not so great a thickness is exposed there. 



Long point and Short point, the two southern peninsulas of Point-au-Roche, are 

 two north and south anticlinal folds of these same strata. 



GRAND ISLE 



At the southern end of South Hero, Grand isle, is an extensive, transversely 

 eroded, north and south anticline, which exhibits in series, beginning with the top 

 of the Calciferous, the entire section of the Chazy, 315 feet in thickness, followed, 

 after an interval, by 35 feet of Black River strata, and, after another interval, by 23 

 feet of the lower Trenton beds. 



CHAZY VILLAGE 



Excellent exposures of the Black River are shown at two of the quarries in Chazy 

 village, Clinton county. New York, and in the bed of the Chazy river. The lowest 

 beds following the strata of the upper Chazy are of a dove-colored barren limestone, 

 perhaps belonging to the Birdseye, followed by the distinctive Black River strata 

 which here have a thickness of 34 feet. It is doubtful whether these beds extend into 

 those of the Trenton proper. Characteristic Black River fossils occur throughout. 



ISLE LA MOTTE 



Several sections of the Black River and of the Trenton are shown on isle la Motte, 

 but none of them are continuous. On the eastern side of the island an excellent 

 example is afforded of the Utica shales faulted sharply down against the Trenton. 



HIGBGATE ■ SPRINGS 



The Highgate Springs section is in the form of a steep north and south anticline, 

 which at its southern end is curved sharply to the westward. The crest of this 

 anticline has then sufiered erosion, so that the whole series of faunas from the 

 Chazy to the Utica is showai in consecutive thin bands, extending east and west 

 on each side of the crest. It was this condition of affairs that gave to Professor 

 Marcou the idea of the development of colonies or lenticles containing precursory 

 faunas at this place.* 



*J. Marcou: Bull. Soc. Geol. France, part iii, vol. ix, 18S1, pp. 14, lu. 



