May 13, 1875] 



NATURE 



39 



sages enclosed by bone ; the centra of the vertebrae amphicoelian ; 

 the coracoid short and rounded ; the ala of the ilium high, and 

 its acetabular margin entire ; and the ischium short dorso-ven- 

 trally and elongated longitudinally, with iis acetabular portion 

 resembling that of a lizard. Genera: Stagonolepis, Belodon. 



2. Mesosuchia, with bony plates of the palatine bones pro- 

 longing the nasal passages, and giving rise to secondary posterior 

 nares ; a middle Eustachian canal included between the basi- 

 occipital and basisphenoid, and the lateral canals represented 

 only by grooves ; vertebral centra amphicoelian ; coracoid elon- 

 gated ; ala of the ilium lower than in the preceding, higher than 

 in the next sub-order, its acetabular margin nearly straight ; 

 ischium more elongated dorso-ventrally than in the preceding 

 group, with its acetabular margin deeply notched. Genera : 

 Steneosaurus, Pelat^osaunis, Tdcosaiirus, Teleidosattrus, Metrio- 

 rhyncus {Goniopholis ?, Pholidosaurus ?). 



3. Eusuchia, with both pterygoid and palatine bones giving off 

 plates which prolong the nasal passages ; vertebral centra mostly 

 procoelous ; coracoid elongated ; ala of the ilium very low in 

 front, its acetabular margin deeply notched ; ischium elongated 

 dorso-ventrally, with its articular margin deeply excavated. 

 Genera : Thoracosaunis, Holops, and recent forms. 



The Mesosuchia are intermediate in character between the 

 other two groups ; the Parasuchia, where they differ from the 

 Mesosuchia, approach the Ornithoscelida and Lacertilia, espe- 

 cially such as Hatteria and Ilyperodapedon, with amphiccelous 

 vertebral centra. The Eusuchia, on the other hand, are the 

 Crocodilia which depart most widely from the Ornithoscelida 

 and Lacertilia, and are the most Crocodilian of crocodiles. 

 After indicating at some length the succession of modifications 

 in the above three groups, the author remarked that if there is 

 any solid ground for the doctrine of evolution, the Eusuchia 

 ought to be developed from the Mesosuchia, and these from the 

 Parasuchia, and showed that geological evidence proved that the 

 three groups made their appearance in order of time, in accord- 

 ance with this view. Thus, in the Trias there are the genera Belo- 

 don and Stagonolepis of the sub-order Parasuchia. In the Upper 

 lias we have Steneosaurits {Mystriosaurus) and Felagosaurus, the 

 first represented also in all Mesozoic formations up to the Kim- 

 meridge Clay; in the Fuller's Earth Tcleosaurus and lelddo- 

 saurns occur ; in the Kelloway Rock Metriorhynchus, also met 

 with in the Oxford Clay and Kimmeridge Clay ; in the Wealden, 

 Goniotholis, Macror/iytichus, Pholidosaurus, and unnamed Teleo- 

 saurians ; and in the Upper Chalk, Hyposaurtis ; all belonging 

 to the Mesosuchia. In the Upper Chalk, again, the Eusuchia 

 make their appearance, represented by the genera Thoracosaurus, 

 Holops, and Gavialis (?). How far back the Parasuchia extend 

 in time is not known, but they are not found in any formation 

 subsequent to the Upper Trias. The author described a frag- 

 ment of a skull of a Wealden crocodile, in which the posterior 

 nares are smaller and situated further back than in Metriorhyii- 

 chus or Steneosaurus. Of the nearest allies of the Crocodilia, 

 the Lacertilia and Ornithoscelida, the former may be traced back 

 from the present day to the Permian epoch, and the latter from 

 the later Cretaceous to the Triassic epoch. The author discussed 

 the question whether these types exhibit any evidence of a similar 

 form of evolution to that of the Crocodilia. The cranial struc- 

 ture of the Permian Lacertilia is almost unknown, and the only 

 important deviation from the type of the existing Lacertilia in 

 the skeleton is that their vertebras are amphicoelous, not procoj- 

 lous. With this exception there is no evidence that the Lacer- 

 tilian type of structure has undergone any important change 

 from later Palreozoic times to the present day ; and this change 

 seems to have occurred earlier in the Lacertilia than in the cro- 

 codiles, as a sacral vertebra of a lizard from the Purbecks has 

 the centrum concave in front and convex behind. "With regard 

 to the Ornithoscelida, the author noticed that the researches of 

 American palaeontologists proved the existence of those reptiles 

 in abundance in quite the latter part of the Cretaceous epoch. 

 lie had himself indicated the existence of varied forms of Dino- 

 sauria in theTiias. He confirmed his former opinion that Zaii- 

 clodon from the Upper Keuper of Wlirtemberg is a Dinosaur, 

 and probably identical with Peratosaurus (von Meyer), in which 

 case its afhnity to Megalosaurus is exceedingly close. He cor- 

 rected a statement in a former paper with regard to the ilium of 

 the Thecodontosaurians, which he had turned the wrong way, 

 and stated that when regarded in its proper position this ilium 

 is much more Lacertilian than that of Megalosaurus. From this 

 and other evidence of detail he inferred that the Triassic Theco- 

 dontosauria were devoid of some of the most marked peculiari- 

 ties of the later Ornithoscelida, while the most ornithic pf the 



latter belong to the second half of the Mesozoic period. The 

 oldest cro odiles oiffi r less than the recent ones from the Lacer- 

 tilia, and the oldest Ornithoscelida also approach a less difTt-ren- 

 tiated Lacertilian form, the two groups seeming to crnvtrge 

 towards the common form of a lizard with Ci'ocodilian verreSrcc. 

 Celiosaurus is also a reptile with a vertebral systcfn like that of 

 the Thecodontosauria and Crocodilia, but with more Lacertilian 

 limbs, and Steuopelyx may be in the same case. It may there- 

 fore be convenient hereafter to separate the Thecodontosauria, 

 Celiosaurus and perhaps Steuopelyx as a group, " Suchospon. 

 dylia," distinct from both the Ornithoscelida and the Crocodilia 

 (or " Sauroscelida "). 



" On the remains of a fossil forest in the Coal-measures at 

 Wadsley, near Sheffield," by H. C. Sorby, F. R.S., Pres. R.M.S. 

 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.—" On Favistella stellata 

 and Favistella caltcina, with notes on the affinities of Favistella 

 and allied genera," by Mr. H. Alleyne Nicholson, F.R.S.E. 



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, con- 

 sisting of plates of ice eight inches square, placed in a wooden 

 chuck three 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, and the other pressed against it. Four pounds 

 of ice were reduced to water at the rate of i|: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 pro- 

 moted melting. When this experiment was tried in a room at 

 54° F. with the same apparatus without any outer case, the fric- 

 tion of the ice in motion, at the above pressure, increased the 

 production of water 3I times above the rate observed when the 

 ice was still and exposed to a temperature of 54° F. The amount 

 of heat evolved was nearly as much as in oak moving upon oak 

 well lubricated, and the coefficient of friction was between OT 

 and 0'2. Glacier motion is impossible without a continual 

 supply of water to lubricate the bottom. No doubt the action of 

 denudation by glaciers produces heat to a small extent. The 

 water obtained by melting the surface of the glacier by the sun's 

 heat in the glacial period could not be sufficient alone. The 

 position of deep lakes in all parts of the world in immediate 

 connection with mountains, and never in places away from 

 mountains, shows that lakes are integral parts of mountains ; 

 and, in fact, lakes are deepest exactly where the glaciers, once 

 covering the mountains, were in a position to act as lake exca- 

 vators. There can be no doubt ;nat all deep lakes in the world, 

 including those in Central Africa, below the Equator, are purely 

 of glacial origin, and that the cold in the glacial period was 

 nearly equally intense in the southern and northern hemispheres. 

 The surface-ice would move much faster than the bottom ice, 

 and the side-ice than the surface- ice, and therefore fractures 

 would be continually occurring through all parts. The water 

 produced by this great friction of ice upon ice would fail 

 through the fissures to the bottom. He had pointed out that a 

 glacier moved twice as fast when it was eight times as thick, and 

 the influence of weight on motion must be considered a most 

 important element. The present temperature of a thin glacier 

 was found by Agassiz, from observation, to be one-third of 

 a degree below freezing ; but Mr. Tylor assumed that in such a 

 lake-glacier as he had drawn, and supposed to exist in the glacial 

 period, the temperature might be assumed to be very much 

 below freezing, the greater cold arising from immense evapo- 

 ration and other causes, lie therefore concluded that the water 

 produced by friction of ice upon ice falling to the bottom of the 

 lake glacier through fissures would rapidly freeze, and thus 

 expanding one tenth, would impel the glacier (shod or armed 

 with blocks of stone and sand at the bottom) up a gradient of 

 I in 20, excavating the Swiss and other lakes thirty or forty 

 miles long, and i,2(X3 feet deep, in this manner. Mr. Tylor 

 calculated that with half the work per annum of mean lake- 

 excavation the lake of Zurich could be excavated in 15,000 

 years. Prof. Ramsay had pointed uut, from geological evi- 

 dence, that such lakes have been excavated by ice, but he dd 

 not indicate how this was mechanically possible (see Quarterly 

 Journal, 1862). Mr. Tylor referred again to his experiment 

 when the pressure was only 2 lbs. on the inch. In a large glaciei 



