THIRD REPORT OF THE DIRECTOR 190b 57 



highly significant discovery. The Shawangunk grit throughout its 

 extent along its western ridge from Ulster county into the Kitta- 

 tinny mountains of New Jersey and on its eastern from Skunnemunk 

 mountain, Orange co. to Green Pond, N. J., had never furnished 

 fossils until the work of the past season brought them to light. In 

 some of the Orange county exposures it has been found that above 

 the basal conglomerate of the formation through the grit layers for 

 a thickness of about 600 feet there are frequent repetitions of thin, 

 black shale layers, inconstant in extent and in number along the 

 outcrops and most of them bearing the remains of merostome 

 crustaceans, of the genera Eurypterus, Pterygotus, Hughmilleria 

 and their allies. The fauna must have been an extensive one as the 

 remains are various and abundant but the preservation leaves much 

 to be desired especially in the case of larger crustaceans whose sur- 

 face has afforded opportunity for shearing and consequent deforma- 

 tion or destruction of the parts. Yet in some respects the preserva- 

 tion has been remarkably favorable for small individuals and these 

 shales have afforded the most diminutive examples of these inter- 

 esting creatures yet brought to light. The presence here of the 

 genus Hughmilleria, heretofore known only in the Pittsford shale 

 at the base of the Salina series in Monroe county, is sufficient evi- 

 dence of the contemporary age of this arenaceous mass. 



In themselves the fossils are extremely interesting affording 

 some details of ontogeny not before recorded for these ancient 

 ^lerostomes. It is entirely evident in the writer's opinion that these 

 crustacean faunules running through the strata for so great a thick- 

 ness indicate temporary and very changeable brackish water pools 

 OA^er the surface of a rapidly accumulating delta derived from the 

 drainage of the high folded lands to the northeast, the deposit 

 laid down in an embayment entirely separated from the salt pans 

 and Dead Sea conditions of central and western New York by a 

 barrier lying approximately in the present position of the Helder- 

 berg mountains. 



Utica shale at Otisville. The Shawangunk grit at Otisville lies 

 iinconformably on the so called " Hudson River " shales and the 

 exposures recently created at this spot have afforded some light on 

 the proper correlation of the parts of this vast homogeneous for- 

 mation. These rocks near Otisville have afforded a considerable 

 number of ' graptolites and the brachiopod Schizocrania 

 f i 1 o s a . The leading species of graptolites are Climacograp- 

 tus typicalis, C. bicornis and Diplograptus 



