GEOLOGY OF THE POUGHKEEPSIE QUADRANGLE 6/ 



glo^rierate, shown at the south end and in the central part of the 

 quarry, to a dense fine-grained mud rock at the northern part. The 

 bedding surfaces are distinct, and good-sized blocks, frequently a 

 foot or more in thickness, have been removed. The rock has been 

 ■weakened by blasting. It still breaks with difficulty into thin irregu- 

 lar pieces that are often crowded with fossils and their fragments. 

 The removal of the mud rock at the south end of the quarry has 

 exposed the basal conglomeratic portion which contains abundant 

 crinoid stems, colonies of Solenopora compacta and some 

 brachiopods. The quarry faces east. The beds of limestone strike 

 n. 40° e. and dip 42° s.e. At the top of the quarry, under the bank 

 and at the summiit of the ridge the rock changes to a chamois or 

 gray color but retains the same strike and dip. 



About seven or eight feet in thickness have been preserved of the 

 finer-textured blue mud rock at the north end of the quarry. 

 Fossils are distributed through it, but could be removed in numbers 

 only from the surface layers. The rock has yielded : 



Orthis pectinella 31 



Plectambonites sericeus 18 



Dalmanella testudinaria 13 



Strophomena alternata i 



Orthis lynx 3 



Streptelasma sp. (resembling parvula ) . 2 



Chaetetes lycoperdon 3 



Ceraurus pleurexanthemus (probably ) ; 3 



Platynotus trentonensis (probably) i 



Calymmene senaria , 6 



Fhacops sp. (probably) I 



lllaenus crassicauda (probably) i 



Os-tracod (undetermined) i 



At the western base of the ridge, somewhat to the southwest of 

 this quarry, and now completely hidden by thick' underbrush within 

 the edge of the woods, is another and older quarry from which it 

 appears the rock was removed and burned for lime a good many 

 years ago. Solenopora compacta was noted here. 



The width of the dark blue limestone stratum on the east is prob- 

 ably less than a score of feet. A small diagonal fault crosses the 

 limestone just w^est of the road that ascends to the sheep pens. 



The blue rock of the quarry is the same as that at Pleasant Valley 

 and Rochdale. The chamois-colored or gray rock is assumed to be 

 the Beekmantown (as qualified above). 



