HUDSON RIVER BEDS NEAR ALBANY 549 



the deposition of large boulders proceeds are evidently not favor- 

 able to a benthonic fauna, the scarcity of fossils in the matrix 

 appears natural; and the view of the continued existence of the 

 fauna of the pebbles, in some adjacent region, and its occasional 

 incursion into the graptolite province seems to be the better sup- 

 ported. This would mean that the Normans kill graptolite fauna 

 and the mollusk and trilobite fauna of the conglomerate with 

 lower Trenton aspect were synchronous. The presence of Tren- 

 ton fossils in so-called Hudson river shales has been proved be- 

 fore (see p. 536). So has the resting of these shales immediately 

 on lower Trenton limestone beds in the regions to the east (33) 

 and to the south, near Poughkeepsie (21). 



Following up the Moordener kill to the base of the second 

 falls, black shales with intercalations of hard, black chert beda 

 and some thinner sandstone and limestone bands are passed^ 

 and at this point a conglomerate bed, 13 feet thick and flanked 

 by thinner conglomerate beds, crosses the creek. On account of 

 the disturbed character of the region, this bed may be identical 

 with that first mentioned. The shales continue to the third 

 falls, where a third conglomerate bed, 20 feet thick, is met with. 

 Then follow coarse sandstones in layers from 2 to 4 feet thick, 

 and sandy shales, and above them black, fissile, argillaceous 

 shales with many thin intercalations of dark limestone and sand- 

 stone. After a break of some 300 feet, dark gray, fissile shales 

 again appear, and these continue to the bridge over the Moor- 

 dener kill on the road between Castleton and Schodack depot 

 (Brookview). Just below this bridge, in steel gray, somewhat 

 sandy, argillaceous shales, numerous excellently preserved speci- 

 mens of Corynoides calicularis were found. Thia 

 occurrence suggests that all these beds may belong to the Dicello- 

 graptus zone. 



A mile and a half farther up, the creek passes again over 

 glazed gray and black shales and bluish quartzite beds, followed, 

 below Dickerman's mill, 2 miles below Schodack Center, by the 

 green and purple slates and grits of the Cambric formation. 



