10 PROCEEDINGS OF THE ACADEMY OF [1898. 



On Instruction and Lectures. — Uselma C. Smith, Benjamin 

 Smith Lyman, Samuel G. Dixon, M. D., Philip P Calvert and 

 Samuel N. Rhoads. 



Standing Committee of Council on By-Laws. — Isaac J. 

 Wistar, Theodore D. Rand, Arthur Erwin Brown, Benjamin 

 Sharp, M. D. 



The Birdsboro Trap Quarries. — Mr. Theodore D. Rand re- 

 marked that the increasing demand for good roads has caused search 

 to he made for the best material conveniently available. Not long 

 ago Mr. John T. Dyer who has long wrought the extensive lime- 

 stone quarries near Howellville, Chester Co., undertook the quarry- 

 ing of trap rock on Hay Creek, a little over a mile southwest of 

 Birdsboro, near Reading, Pa. The trap, probably a diabase, has 

 come up through the Red Rocks, forming high hills on both sides of 

 the creek, the valley of which has enabled the Wilmington and 

 Northern R. R. to descend into the Schuylkill Valley. The re- 

 markable feature of this trap is the evidence of intense dynamic ac- 

 tion more recent than the rock itself. There are three quarries, 

 two on the right and one on the left bank of the creek. 



The lower quarries show breasts of about a hundred feet in height, 

 increasing as the quarrying proceeds further into the steep and high 

 hills. Everywhere, except some portions of the upper quarry, the 

 rock is very full of joints, the major striking N. 65° E., the others 

 seemingly in almost every direction, as if the rock had been crushed 

 by a very sudden pressure. The joints show, usually, slickensides 

 on their surfaces, but there is strong cohesion through the joints, 

 but much less than through the rock itself. These joints, of course, 

 greatly facilitate the quarrying and crushing, though sometimes in- 

 terfering with the drilling. At the upper quarry some rock was 

 seen much resembling that of French Creek, and capable, like it, of 

 being quarried in large and regular masses. In this quarry, also, 

 were found some specimens of heulandite and probably laumontite, 

 giving promise of fine specimens. 



The present output of the quarries is eleven hundred tons of crushed 

 stone per day. The consumption of this large amount shows the 

 remarkable increase in the use of this material. 



A striking feature was the cleanliness of these quarries. The 

 blasting is done usually twice a day, but after each blast some of 

 the quarrymen are detailed to fork up the fragments, so that the 

 horses and carts travel over a smooth and level surface. The horses 

 were of a quality rarely seen in quarry work, and evidently were 

 well cared for aud well treated, while the men worked industriously, 

 without the vigorous language too often heard in quarrying opera- 

 tions. 



