866 Beds upon which Philadelphia stands. 



As to organic remains, while digging a cellar in Oak street, 

 in the Northern Liberties, a large mass of madrepore was found 

 in sand, eight feet below the surface. This happened so near to 

 the Delaware, that I conjecture it came there with alluvial 

 matter. I have never been able to detect any organic remains 

 in the gravel ; but in digging a well at the south end of the naval 

 asylum, built by the United States, after passing the various 

 strata above described, about on a level with the Schuylkill 

 river, the workmen struck upon a bed of black alluvial, resem- 

 bling river mud, in which was found wood, leaves, and bark ; the 

 latter so sound that it retained its natural colour, and upon in- 

 spection it was pronounced by good judges to have belonged to 

 the hemlock. Before reaching this stratum of mud, tbe workmen 

 found some pretty large stones, resembling paving stones. 



It would then seem, that before the deposit of this diluvial mat- 

 ter, there was a vast valley at this place, through which the 

 Schuylkill river ran its peaceful course; that the bed of the river 

 was strewed in the usual way with pebbles, and its banks shaded 

 with hemlock trees. 



About 38 years ago, a friend of mine dug a sink in a cellar, at 

 the N. W. corner of Cherry and Seventh street, Del. : at the 

 depth of about thirty feet from the bottom of the cellar, which 

 was eight feel below the surface of the earth, the workmen 

 found black marsh mud, in which were buried hickory nuts, 

 acorns, leaves, and a log of wood ; the latter in a high state of 

 preservation. Before coming to the mud, the workmen passed 

 through a stratum of plastic clay, a stratum of gravell)' sand, 

 coloured with iron, and a stratum of fine white sand. This fur- 

 nishes an additional proof, that the present site of Philadelphia 

 was, in ancient times, a hollow basin, or valley. 



How gratifying thus to withdraw the curtain of time, and pene- 

 trate into the secrets of a remote antiquity. The apparently 

 insignificant gravel stones which we indiflTerently tread under 

 foot, when submitted to the scrutiny of the geologist, are found to 

 be so many historical medals. They are indeed mute ; but when 

 compared with their parent rocks, and the beds which they now 

 occupy, they speak eloquently of important changes this planet 

 has experienced, and which tradition has confirmed. 



In the clay of the site of Philadelphia are found some objects 

 which are supposed by many to be fossil remains ; others believe 



