Editorial Comment. 423 
On Friday a lively discussion followed the reading of Dr. 
Crosskey's report on the erratic blocks, and his paper on a high 
level boulder-clay in the Midland district. No new points, how- 
ever, were brought out in the paper, in which the author advo- 
cated the distribution of these boulders by the action of floating 
ice, rather than by that of glaciers, a view in opposition to that 
entertained by several speakers in the discussion that followed. 
All who took part, together with the author of the paper and 
the president of the section, spoke in feeling terms of the late 
Prof. Carvill Lewis, whose early and unexpected death has 
deprived American geology of a promising worker in the glacial 
field. 
The work on Saturday commenced with a comparison by Prof. 
Marsh of the principal forms of Dinosaurians in Europe and 
America. Prof. Marsh's views being already in print, it is not 
necessary to repeat them here. In replying, Prof. Seeley, while 
difCering from the speaker in some points, took occasion to 
express high appreciation of Prof. Marsh and his labors in 
American vertebrate palaeontology. 
Prof. Osborn then made some remarks on the development of 
the mammalian molar teeth to and from the tubercular type. 
He pointed out a line along which the conical tooth of the rep- 
tile may have passed to the form with three tubercles. This 
was during the Oolitic age. Then came the Cretaceous, with its 
single mammal, breaking the chain of evidence; and when that 
had passed away, the mammalian molar was found in the lower 
Eocene. Prof. Seeley added a little further evidence of the same 
kind, and Prof. Gaudry gave a short address (in English) on the 
comparative size of some of the fossil mammalia. Two short 
notes followed, read by the secretary in the absence of their 
authors, on the amount of carbonic acid in the atmosphere in 
past ages, and on the occurrence of a gneissic pebble in the 
Halifax coal. 
Two geological excursions were made on Saturday afternoon 
to the great oolite quarries at Box, where the workings are car- 
ried on underground at a distance of about two miles from the 
opening and to a long section of the Carboniferous limestone, 
passing down into the Old Red sandstone without unconforma- 
bility. Many members took advantage of the opportunity of 
visiting the similar but much grander display of the same rocks 
