634 DR. E. KCETTLITZ ON THE [T^OV. 1 898, 



in part of stratified rocks, sometimes composed of sand, shale, or 

 micaceous sandstone containing lignite ; a brown laminated siliceous 

 rock having the appearance of a tuff proved not to be so when 

 examined microscopically and chemically by Mr. Teall. 



The lower part of some at least of these intermediate layers is 

 formed by a tuff- like rock, which decomposes readily and has been 

 described by Mr. Teall as decomposed basalt, basaltic scoria, and 

 basalt-tuff. At one spot between the first and second tiers this inter- 

 mediate layer was an agglomerate containing some large angular 

 blocks. 



The basalt immediately overlying the laminated beds is always 

 vesicular. The vesicles are not uncommonly filled with calcite, or 

 palagonite, and are often elongated to as much as 1 or even 3 inches, 

 their long axes being at right angles to the stratified beds below, 

 which beds show no appreciable alteration by heat. 



At a spot near Cape Plora, at the junction between the basalt and 

 the underlying Jurassic beds, I obtained a fragment of an ammonite 

 which Mr. E. T. Newton has identified as Ammonites Lamberti ; 

 while Mr. Teall describes the rock surrounding this specimen as 

 decomposed basalt or basaltic tuff. One specimen of this tuff is 

 traversed by parallel veins of calcite. 



Frequently I have found branches and stems of trees embedded 

 in the basalt, and this most commonly in the second tier. In one 

 instance a branch 3 inches in diameter was in the condition of 

 charcoal, and the surrounding material appeared to be decomposed 

 basalt and contained analcime. 



The facts which lead me to think that the basalt (for the most 

 part, at least) was not intruded as sills between older rocks, but was 

 laid down on the surface as sheets of lava, may be thus briefly 

 stated : — 



(1) The frequency with which beds of tuff-like material are 



interposed between the tiers of basalt, and underlie beds of 

 stratified rock. 



(2) The presence of petrified and carbonized wood in the basalt. 



(3) The beds of tuff-like rock containing plant-remains apparently 



interstratified with the basalt, which are thin and, to all 

 appearance, undisturbed. 



(4) The more vesicular character of the basalt, so generally 



found, at its upper and lower margins. 



(5) The seemingly undisturbed character of some of the thinner 



among the stratified layers between the tiers. One such 

 layer, about 18 inches thick, I traced for some 600 yards. 



(6) The little or no alteration by heat to be detected in the 



stratified rocks immediately in contact with the basalt. 



The evidence for the age of these basalts necessarily depends upon 

 the strati graphical position of the fossiliferous rocks with which 

 they are associated and their relation to these rocks : the latter 

 question has already been considered. The fact that the basalt is 



