PKOCEEDINGS OF THE GEOLOGICAl. SOCIETY. 1 1 7 



synclinal fissures. All the beds of lignite and brown coal worked 

 near Cassel*, and at other places of which I have a knowledge, dip 

 against the slope of the mountain, if they are penetrated by a basalt- 

 dyke and covered by a layer of basalt ; whereas valleys between 

 such mountain-ridges are due to the anticlinal between the synclinal 

 fissures. 



This may, I think, be well explained in the following way : — 

 During the process of folding and faulting the hard crust of the 

 earth was pressed downwards more particularly in the synclinal 

 lines, and, if in those places any molten magma existed beneath the 

 crust, being compressed, it escaped by the readiest way, which was 

 through the synclinal fissure opening downwards, like a reversed 

 funnel (see the section in the above-cited ' Jahrbuch,' 1885, pi. i.). 



Now our Middle and Upper Miocene basalts are in every way 

 similar to many lavas of recent volcanoes, not only in petrological 

 composition, but also in their geological conditions, for in several 

 basalt cones in Hesse and in the E,hou, observed by Professor Strong 

 and myself, the crater-form has escaped erosion by weathering, and 

 these craters are associated with scoriae or slags, tuffs, and lapilli. 



It appears to me, therefore, not unlikely that the cause of erup- 

 tion of recent lavas may also be similar, and that it may be the 

 same as that of structural earthquakes ; whereas the outburst of 

 gas, vapours, dust, ashes, &c., may partly result from water, passing 

 downwards through fissures and being overheated and vaporized. 

 This may account for the statement of many authors that those 

 violent detonations &c. of volcanoes are quite independant of the 

 rather quiet outflowing of incandescent lava. 



I would submit these observations to English geologists, as they 

 are specially interested in volcanic energy and in all that is con- 

 nected with volcanoes, and as we are indebted to them for a great 

 deal of what we know about vulcanicity. 



2. '' On the Origin of the Basins of the Great Lakes of America." 

 By Prof. J. W. Spencer, M.A., Ph.D., E.G.S., State Geologist of 

 Georgia. 



3. " On Ornithosaurian Remains from the Oxford Clay of North- 

 ampton." By R. Lydekker, Esq., B.A., F.G.S. 



4. " Notes on a ' Wash-out ' found in the Pleasley and Teversall 

 Collieries, Derbyshire and Nottinghamshire." By J. C. B. Hendy, 

 Esq. (Communicated by Dr. W. T. Blanford, F.K.S., E.G.S.) 



The following specimens were exhibited : — 



Specimens of remains of Wiamplwrhijnchus Jessoni, Lyd., from 

 the Oxford Clay of Northampton,' exhibited by Pi. Lydekker, Esq., 

 E.G.S., in illustration of his paper. 



[* See also Quart. Journ. Geol. Soc. vol. xi. pp. 129 & 134, figs. 1 & 2. — Ed.] 



