p. F. Schneider — Eruptive Dikes in Syraeuse. 25 



abundant. No traces of the enclosing walls of the dike could 

 be found. Sheet material banked it on the west, and heavy 

 Pleistocene clays with quicksand beyond them formed the 

 eastern border. At Green st. the enclosing walls are perfectly 

 shown, and it was hoped that further excavations would open 

 up other exposures showing the contact phenomena, but this 

 did not occur. The other excavations, where the strike of the 

 dike would seem to indicate its existence, were all on higher 

 ground with heavy mantles of drift which even this deep 

 sewer did not penetrate. 



One other opening occurred in a return sewer on Highland 

 St. The excavations passed for 180 feet through rock which 

 was thought at that time might be merely sheet material from 

 the dike, but I am now convinced that it was another parallel 

 dike. This rock, while almost as difficult to excavate as that 

 of the first dike, decayed very rapidly after a- few days expo- 

 sure. It also had more or less of a massive wedged appearance 

 in the trench like the first dike, and quite unlike the banded 

 appearance of the sheet, and furthermore contained many 

 inclusions. It also contained numerous small red crystals, 

 the " rubies," which the neighboring school children collected 

 in abundance. ]N^one of these peculiar forms were found in 

 the De Witt, or in any of the Syracuse dikes at Green st. 

 Some of them appeared to be perfectly crystaUized garnets, 

 but so rapidly did this rock break up, especially when dry, 

 that they usually fractured soon after being exposed, A 

 few crystals of greenish color were also obtained from this 

 same rock, but none of either kind were noticed in the hard, 

 firm variety. All. of these facts would seem to indicate a 

 second dike more or less parallel to the first and less than 250 

 feet aw^ay. Through this second dike the excavations must 

 have passed very nearly longitudinally, while the sewer proper 

 crossed the main dike at nearly right angles. As the return 

 sewer stopped when connection had been made with the sewer 

 proper, and as the excavations up to this point did not pass 

 through to the farther side of the dike, no facts as to its width 

 can be given. The proximity of these dikes to those at Green 

 St., which are less than a mile away, suggests some under- 

 ground connection, and inasmuch as their general direction is 

 the same they may be merely a continuation of those dikes. 

 The intervening space has frequently been trenched, and at 

 such times the excavations have been carefully watched for 

 evidence of the dikes without revealing any trace of them. 



Syracuse, N. Y. 



