134 PROCEEDINGS OF THE ACADEMY OF 



The following paper was presented for publication : 

 " A new classification of the North American Falconidse, with de- 

 scriptions of three new species." By Robert Ridgway. 



Prof. Leidy directed attention to a preparation of the trunk of an adult 

 male subject, from the dissecting room of the University, iu which all the vis- 

 cera were reversed in the order of their usual position. The heart is reversed 

 in position with its apex directed to the right. The aorta descends on the 

 right side ; and the caviB are placed on the left of the vertebral column. 

 The liver is placed in the left, the spleen in the right side. The stomach is 

 reversed, and the large intestine commencing in the left iliac region termi- 

 nates in the rectum from the right side. 



Theo. D. Raxd called the attention of the Academy to a remarkable expo- 

 sure of rock on the North Pennsylvania Railroad, between Abingdon and Edge 

 Hill stations, about eleven miles from Philadelphia. The rock is Potsdam 

 sandstone, highly micaceous, in strata nearly vertical, and divided by frequent 

 joints. Its strike is about N. by E. At the point mentioned a quarry has 

 been opened following the crest of the hill, the northern end of the quarry 

 giving therefore a section. At the bottom of the excavation the layers seem 

 undisturbed and perfectly vertical, but above they are thrown to the south- 

 west and crushed and broken in a remarkable manner, the layers nearest the 

 surface being horizontal or even dipping to the S. W., but still retaining their 

 relative positions. The breaks in the rocks are fresh and sharp, and the 

 spaces between them empty, and the whole appearance is as if a very recent 

 force acting near the surface had thrown them from a vertical into their 

 present positions. Some of these spaces were two or three inches in width 

 and apparently of great depth. 



It is probable, however, that it is due to a folding of the strata, as in the 

 cut of the Railroad immediately west of this exposure. The rocks of the quar- 

 ry appear perfectly vertical while south of them, probably fifty feet, is a well 

 defined anticlinal axis or fold. Still the broken, not bent condition of the 

 rocks, their very marked and sudden change from the vertical, the freshness 

 and sharpness of the fractures seem almost irreconcilable with a fold taking 

 place as long ago as this anticlinal axis, and it is well worthy of examination 

 by geologists. 



December 27th. 



The President, Dr. Ruschenberger, in the Chair. 



Thirty-four members present. 



On motion, the election of members was postponed until the next 

 meeting for business. 



Prof. Leeds called attention to an interesting geological phenomenon in 

 the vicinity of Wayne station on the Germantown Railroad, about three miles 

 from Philadelphia. At the point where Wayne street cuts through a fold in 

 the micaceous schists of this district, there occur huge imbedded boulders of 

 very hard compact hornblende rock. The matrix of mica schist has the ap- 

 pearance of an altered argillaceous slate, and rapidly decays on exposure. 

 The hornblende rocks are thus left protruding above the soil, aud would be 

 difficult to account for if attention had not previously been called to them in 

 place. As occurring in the schist, they are rounded upon their corners and 

 edges and smooth upon the sides. It does not appear an improbable con- 

 jecture to suppose that they constituted a part of a primitive surface forma- 

 tion perhaps the original earth crust which was broken up before the de- 



[Dec. 



