HARD WICKE 'S S CIENCE - G OS SI P. 



41 



habits, and about the size of a large wolf. In general 

 characters it resembles the Hytruodon, but had only 

 four incisor teeth, and seven lower n.olars, on each 

 side. The top of the skull is marked by a very 

 large sagittal crest. Prof. Marsh has called it 

 Dromocyon vorax. 



Proceedings of the Geologists' Association. 

 — We have received No. 9 of the fourth volume of 

 this work, giving papers on the ' ' Geology of Lewis- 

 ham," by H. J. Johnson Laris, F.G.S. ; "On the 

 British Palteozoic Arcadcc," by J. Logan Lobley, 

 F.G.S. ; on "The Bagshot Sands of the Isle of 

 Sheppey," by Major F. Duncan, F.G.S.; and one 

 on " The Mill-Hill Cutting, Sheppey," by W. H. 

 Shrubsole. There are, also, four well-written de- 

 scriptions of excursions made by the members of the 

 association to various places of geological note. 



"The Intrusive Character of the Whin 

 Sill of Northumberland." — This was the sub- 

 ject of an important paper recently read before the 

 Geological Society by W. Topley, F.G.S., and G. 

 A. Lebour, F.G.S. The authors stated that the 

 Carboniferous Limestone series of the North of 

 England contains a bed (or beds) of basalt, known as 

 the " Whin Sill," regarding the nature of which 

 opinion has long been divided. Some writers regard 

 it as truly interbedded and contemporaneous ; others 

 look upon it as intrusive, and as having been forced 

 laterally between the planes of bedding. The latter 

 opinion is that held by the authors, who stated that 

 through South and JNIid-Northumberland there can be 

 no doubt as to the intrusive character of the Whin 

 Sill. This conclusion can be established by the line 

 of outcrop of the trap, and also by the evidence of 

 individual sections. A review of the literature on the 

 subject was given by the authors, showing that the 

 opinions of geologists are very much divided as to the 

 nature of the Whin Sill. But amongst the practical 

 miners of the North of England there are very few 

 who will admit any doubt that the Whin lies evenly, 

 and at one constant horizon, amongst the strata. 

 Clear cases to the contrary are looked upon as merely 

 local variations, possibly due to successive eruptions 

 of submarine lava. The Whin Sill serves them as a 

 definite line, and the limestone next above it is always 

 called the " Tyne Bottom Limestone." The question 

 is thus of considerable economic importance. It is 

 also of interest in reference to the volcanic history of 

 Britain and to classification. Prof. Phillips took the 

 Whin Sill 'as the base of the Yoredale Series ; the 

 Gi'eat Limestone he regarded as its top. But the 

 work of the Geological Survey has shown that the 

 Whin Sill lies at different horizons in different places ; 

 sometimes it even lies above the Great Limestone 

 itself. In other words, the Whin Sill, zuhich is sup- 

 posed to mark the base of the Yoredale Series, some- 

 titnes lies above the limestone which forms the top of 

 that series. With the disappearance of the supposed 



base-line of the Yoredales goes also any good reason 

 for drawing a line here at all. The so-called "Tyne 

 Bottom Limestone " cannot be traced definitely 

 through Northumberland, and the beds above and 

 below this horizon have the same general character. 

 The authors traced the Whin Sill through North- 

 umberland, as far north as Dunstanborough Castle, 

 showing the varying positions at which it occurs in 

 the Limestone series, and noting points of interest in 

 some of the sections. The Whin shifts its position 

 amongst the strata to the extent of 1,000 feet or more. 

 It frequently comes up in bosses through the bedded 

 rocks, and bakes the beds above it quite as much as 

 those below, especially when those beds consist of 

 shale. As to the age of the Whin Sill, nothing 

 definite can be said. It is frequently thrown by faults 

 and lodes. There is no certain case of its being 

 unaffected by faults which throw the neighbouring 

 rocks, although there are a few doubtful cases which 

 seem to point in this direction. As the Whin Sill 

 does not approach the Permian area of Durham, the 

 fact that some of the faults there are believed to be 

 pre-Permian cannot be applied as a test of age in this 

 case. In other districts in Britain in which intrusive 

 basaltic sheets occur amongst the Carboniferous rocks, 

 there is good reason to believe that in most cases they 

 are pre-Pennian, or at least pre-Triassic. Whether 

 or not this be the case with the Whin Sill cannot be 

 determined. No light is thrown on this question by 

 the composition of the rock. Mr. Allport has shown 

 that it resembles, in all essential characters, the 

 basalts of other Carboniferous districts, some of 

 which are possibly contemporaneous, some certainly 

 intrusive. 



NOTES AND QUERIES, 



Ants and Ant-eaters. — Having read the follow- 

 ing account in a book about ants and ant-eaters, I 

 thought it would interest the readers of SciENCE- 

 GossiP. A traveller in South America says : — " We 

 rode over hills used as pasture-ground, which were 

 literally dotted with the upright and fallen columns 

 that had been erected by the termites or white ants. 

 These curious edifices, and their still more curious 

 architects, have always had a great attraction for the 

 naturalist. The hillocks are conical in their shape, 

 but not with a broad base and tapering point as those 

 built by the termites of Africa. Exposure to the sun 

 has rendered them exceedingly hard, and doubtless 

 many that are seen in the uplands of St. Paulo and 

 Minas-Geraes are more than a century old ; for houses 

 whose walls have been built from the same earth are 

 still in existence which were built by early settlers in the 

 seventeenth century. Sometimes the termites' dwell- 

 ing is overturned by the slaves, the hollow scooped out 

 and made wider, and it is then used as a bake-oven 

 to parch Indian corn. In my ride over Soldade I 

 saw a number of very large vultures, who during the 

 rain had taken refuge in the houses that had been 

 vacated by the white ant. These insects do not, how- 

 ever, always dwell in columnar edifices of three and 

 six feet high . I have seen in some portions of Brazil 



