16 TRANSACTIONS OF THE [oCT. 11^ 



ory is supported by no less authority than that of Professor 

 Dana. But after a careful and prolonged examination of most 

 of the localities on which this theory is based, I am of the opin- 

 ion that the occurrences can be more satisfactorily explained, 

 and adhere to my belief that they are Archaean. It may here be- 

 remarked that Mr. Merrill is about undertaking a critical study 

 of Westchester County, and that we may promise ourselves the 

 presentation ere long of evidence which will go far towards prov- 

 ing the truth of one or the other hypothesis. 



Triassic Rocks. — No additional exposures of shales, sand-^ 

 stones, or trap have come to light since my first communication. 

 The wells of the Crystal Water Company are within the area 

 surmised to be underlaid by the Triassic red rocks, being between 

 the southwestern end of the trap dyke and the serpentine hills, 

 but were bored in the drift. 



Cretaceous Strata. — Here also there are no additional expo- 

 sures to record. The kaolin and fire-clay continue to be mined 

 in considerable quantity near Kreischerville. From the known 

 outcrops and exposures, there must be a large tract of territory 

 underlaid by these valuable materials, though much is deeply 

 covered with glacial drift. The discovery of vegetable fossils 

 similar to those of Woodbridge and South Amboy, N. J., has 

 already been announced to the Academy and noted in the Trans- 

 actions, Vol. v., p. 28. No opportunity has since been afforded 

 for the collection of additional material at this locality. If, 

 however, the vegetable remains in the ferruginous sandrock at 

 Tottenville are, as they appear to be, Cretaceous, it should be 

 recorded that Mr. Hollick has obtained a considerable addition 

 to his previous collections from that point. He has described 

 the occurrence of these fossils in the "Proceedings of the Nat- 

 ural Science Association of Staten Island " of Dec. 8th, 1883, 

 and compared them with the specimens from Glen Cove, Long 

 Island, in the Museum of Columbia College, which Dr. New- 

 berry has already exhibited to the society. 



Pre-Glacial Drift. — Mr. Hollick has recently found an addi- 

 tional outcrop of this interesting formation. It is near the vil- 

 lage of Woodrow and at considerable elevation, though not as 

 high up as the great deposit on Todt Hill. 



Deposits of Limojiite. — Owing to the low prices obtainable for 

 iron ore, but little work has recently been done on these deposits. 

 Very little material has been excavated, and no new beds have 

 been explored. On Todt Hill there is a small amount of pyrite 

 associated with the limonite, which in its decomposition produces 

 Cojjperas; and this mineral may be noted as new to Staten 

 Island. Dr. Hunt visited the Todt Hill mine with me some 

 three years ago, and has since expressed his opinion that the ore 



