Geological Society of London. 279 



In this paper the author described the occurrence of a number of 

 stumps of Sigillarice in position and with Stigmarian roots attached 

 to them in the Coal -measure Sandstone in the grounds of the South 

 Yorkshire Lunatic Asylum, and mentioned that the authorities of 

 the Asylum, in order to preserve these remains, had erected two 

 wooden buildings over them. The trees seem to have grown in what 

 is now a bed of earthy clay -like shale; there to have dried and rotted 

 down to the level of the surrounding mud, leaving hollow stumps, 

 to be afterwards filled up with the sand now forming the super- 

 jacent bed of sandstone. The stumps exposed were about ten in 

 number, spread over forty or fifty yards of ground. The smaller 

 trunks have four, and the larger ones eight roots ; and the author 

 specially called attention to the fact that, from the position of these 

 roots, by analogy with existing trees, we may infer the direction of 

 the prevalent wind at the time the trees were growing, and that it 

 appears to have been from the west. 



3. " On Favistella stellata and Favistella calicina, with Notes on the 

 affinities of Favistella and allied genera." By H. Alleyne Nicholson, 

 M.D., D.Sc, F.E.S.E., F.G.S. 



The author noticed that Columnaria alevolata, Goldf., has been 

 described by Hall under the name of Favistella stellata, as pointed 

 out by Milne-Edwards and Haime, and discussed the course to be 

 pursued, another Coral from the Trenton Limestone having been 

 described and figured by Hall and other American palaeontologists 

 as Columnaria alveolata, Goldf. The distinction between the two 

 forms consists chiefly in the degree of development of the septa, 

 these being marginal and rudimentary in the latter species, and 

 reaching nearly or quite to the centre in the true C. alveolata, Goldf. 

 He proposed to refer both to the genus Columnaria, accepting Favi- 

 stella as a sub-genus, and retaining Hall's specific name for its type. 

 In case of the identity of Favistella stellata, Hall, and Columnaria 

 alveolata, Goldf., being definitively established, he suggested the 

 name of C. Halli for the species described by Hall as C. alveolata. 

 He also described a new species of the genus under the name of 

 Columnaria {Favistella) calicina. 



Mr. A. Tylor brought an apparatus for determining the heat 

 evolved by the friction of ice upon ice, with a view to explain an 

 important element in glacier motion. The apparatus, consisting of 

 plates of ice 8 inches square, placed in two wooden chucks 3 inches 

 deep, was enclosed in a double sheet-iron case containing ice and 

 salt, and kept at 32° F. One block of ice was rotated, 1 and the other 

 pressed against it. Four pounds of ice were reduced to water at the 

 rate of 1^ lb. in an hour, in consequence of the motion, that is by 

 the heat evolved by friction of ice upon ice, the pressure being 

 2 lbs. on the square inch. Ice evaporates at 32°, and the same 

 quantity of ice was reduced, when still, at about the rate of \ lb. 

 in an hour at 32° F. Air at a higher temperature found its way 

 into the case, and promoted melting. When this experiment was 

 tried in a room at 54° F. with the same apparatus without any 

 1 One chuck revolved 500 times in a minute. 



