432 Miscellaneous — Eurypterus mammatiis. 



nvnisojsLXi^isrEOTJS. 



GrEOLOGY OF THE Straits OF DovER. — The subject of a railway 

 connexion between England and France bas for some time past 

 busied the minds of Engineers. Proposals have been made for a 

 Bridge over the sea, a Tube on its bed, and a Tunnel beneath the 

 bed of the sea. With the third scheme many geological considera- 

 tioDS are of course involved, and we are glad to see that the subject 

 has been ably discussed by Mr. W. Topley, F.G.S., in the Quarterly 

 Journal of Science, for April. Plans for tunnels in two positions 

 have been put forward, the one to be made wholly through the 

 Chalk between Dover and Calais ; the other through the Lower 

 Greensand, and probably the Wealden and Upper Oolites, between 

 Folkestone and Cape Gris-nez. Mr. Topley points out the geologi- 

 cal structure of the English and French coasts in proximity to these 

 proposed tunnels, and gives a little geological map of the land with 

 the probable outcrops of the formations beneath the water ; though 

 on this point he acknowledges there is not sufficient evidence for 

 much exactness. The tunnel from Folkestone would pass through 

 a number of different beds, the changes in which it would be diffi- 

 cult to estimate, for the Lower Greensand and Wealden beds thin 

 out in a very remarkable manner towards the Continent. Moreover, 

 in these beds a good deal of trouble might be expected from water. 

 Mr. Topley therefore points out that the other tunnel from Dover 

 would be the least difficult undertaking. It could be taken for most, 

 if not all the way, through the Lower Chalk, and he shows that very 

 little trouble need be anticipated from water in penetrating this 

 formation. And lastly he mentions that there is no reason to sup- 

 pose that any great fault will be met with during the progress of 

 the work. 



'Eurypterus {Arthropleura) mammatus, Salter. This species was 

 figured and described by Mr. J. W. Salter in 1863. (See Quart. 

 Journ. Geol. Soc. vol. xix. pp. 81-87.) It occurs associated with 

 plant-remains in the " Ferny metal " bed, Pendleton Colliery, near 

 Manchester. It is only known from a series of fragments. 



A recent examination by Mr. W. Carruthers, F.E.S., has fully 

 confirmed the opinion of Mr. Hemy Woodward, that these speci- 

 mens (with two exceptions) are not Crustacean, but Vegetable- 

 remains referable to the Ulodendron. The two portions not be- 

 longing to Ulodendron are referred to Jordan's genus A rthropleura, 

 which may be a Crustacean, but is more probably a gigantic 

 Arachnide ; it is certainly not a Eurypterus. 



