364 GEOLOGY OP OLD HAMPSHIEE COUNTY, MASS. 



angular blocks can have been moved from their place and carried liori- 

 zontally southward, as they have been, without the intervention of shore 

 ice. In a valuable resume of the evidence bearing upon the question of the 

 existence of Triassic glaciers Professor RusselP has expressed his conclu- 

 sion as follows: 



The absence of glacial records seems to warrant the conclusion that glaciers did 

 not enter the basins in which the Newark rocks were deposited. It does not follow, 

 however, that the Appalachians were not occupied by local glaciers. The suggestion 

 that these mountains were higher in the Newark period than now and were covered 

 with perennial snow while the adjacent lands enjoyed a mild climate, seems an 

 attractive and very possible hypothesis, but definite evidence as to its verity has 

 not been obtained. 



With this conclusion I agree, as I have, after much searching, found no 

 decisive proof of the advance of glaciers into the Triassic basin, but much 

 that suggests the presence of shore ice. 



THE LONGMEADOW SANDSTONE. 



This, the well-known building stone, is a deep-red sandstone of rather 

 coarse grain, usually quite quartzose and with aliundant cement of hem- 

 atite. Both the Sugar Loaf arkose and the Mount Toby conglomerate, 

 but more commonh' the latter, grade into this rock. It is generally 

 subsequent to the iirst outflows of trap, but both in Greenfield and 

 in Agawam underlies in part the Deerfield and Holyoke traps, respec- 

 tively. Round or slightly flattened rods of sandstone one-fourth to one- 

 half inch across, often transverse to the bedding, often interlaced, are 

 everywhere abundant and characteristic, and at times the whole mass of the 

 sandstone is made i;p of these ]«-oblematical forms, comnu^idy called fucoids. 

 They seem to me to be ferruginous concretions formed in the sand by iron- 

 bearing solutions derived from the diabase. They are so uniformly present 

 in the beds of this subdivision that they have almost the value of a charac- 

 teristic fossil, and I have fallen into the habit of calling the rock the 

 fucoidal sandstone. Mud-cracks, rain-drops, glazed and curdled surfaces, 

 tracks, and all indications of short and frequent emersion from the water are 

 very abundant. 



The rock appears in an isolated area in the region around Greenfield, 

 and occupies the center of the basin from the tuff' beds in South Hadley 

 southward. It is well exposed at the quarrj^ near Mr. E H. Lyman's house, 



'Correlation Papers, The Newark .System: Hull. U. S. Geol. Survey Xo. 8.5. 1892, p. 53. 



