408 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



especially as regards the Deerfield bed, and that Avitli the poor maps and 

 the small scale used the delineation became more and more inaccurate. 

 Upon the map of 1844 the Mount Tom rang-e is represented much more 

 accurately, a posterior range is given in West Springfield, and three long 

 patches of" "trap tufa and tufaceous conglomerate" are laid down. Upon 

 the map in the Ichnology, 1857, a further advance is made by showing that 

 the Holyoke range consists of two bands of trap with a narrow intervening 

 band of sandstone. The section through Norwottock on the border of the 

 above map is incorrectly colored to indicate tlu'ee bands of trap ; the south- 

 ern band should receive the color of the "trap tufa." Furthermore, in all 

 the copies of the work I have seen the trap tufa has the same color as the 

 crystalline rocks upon the borders of the map, while in the legend a deeper 

 shade of the color is assigned to it. This eiTor has perpetuated itself in a 

 cm-ious way. Upon the small geological map attached to the map of 

 Hampshire County of H. F. Walling (1858) a pink band of crystalline 

 rocks is made to run across from Belchertown to the river south of the 

 Holyoke range. The map is said to be "by Edward Hitchcock." One 

 may infer, I think, that he had very little to do with it. 



In the small map appended to Reminiscences of Amherst College 

 (1863), President Hitchcock gave his final results regarding the rocks in 

 question. He now makes the Holyoke range a single broad area of trap 

 extending east to overhang, with undiminished width, the northern of the 

 Belchertown ponds, and lays down two great areas in Pelham, the one 

 made out by coloring as trap the whole area between the two occurrences 

 detailed below, and the other based upon the area of great bowlders east of 

 Amethyst Brook. 



The geological map of Prof C. H. Hitchcock in Walling's Atlas of 

 Massachusetts (1871) gives a posterior bed in the eastern half of the 

 Holyoke range and the northern part of the Mount Tom range, presenting 

 thus the best results of his father's work. 



In 1875 Prof E. S. Dana presented to the American Association the 

 preliminary results of studies upon the Triassic diabases, undertaken by 

 himself and Mr. Gr. W. Hawes, and in the same year Mr. Hawes printed 

 a series of analyses of these rocks, including one from Mount Holyoke. 

 Although in the main devoted to the Connecticut rocks, these studies 

 reached results applicable to this area, viz: the greater freshness of the 



