PRESIDENTIAL ADDRESS. 381 



system as a final solution of the difficulty. This would be to renounce for ever 

 the claim of this branch of geology to rank as a rational science. I have said 

 enough to show that I am one of those who take a more hopeful view of the 

 future of petrology, confidently expecting it to show, like the past, a record of 

 continued progress. 



The following Papers and Reports were then read : — 



1. The Geology of Portsmouth and District. 



J 



By Clement Reid, F.R.S. 



2. Further Work on the Silurian Rocks of the Eastern Mendips. 

 By Professor S. H. Reynolds, M.A. 



In May 1907 a paper was published in the ' Quarterly Journal of the Geo- 

 logical Society' describing the igneous rocks of the Eastern Mendips, and show- 

 ing that the andesite, which had previously been regarded as intrusive, was 

 interbedded with tuff and rested on a further series of tuffs containing Silurian, 

 probably Llandovery fossils. 



In the latter part of 1907 fresh sections in fossiliferous Silurian rocks were 

 exposed to the S.E. of the Moon's Hill quarry owing to the laying of a line of 

 rails from the Downhead quarry, and at the Leicester meeting of the British 

 Association in 1907 a Committee was appointed to further investigate the Silurian 

 rocks of the Bristol area and of the Mendips. Under the auspices of this Com- 

 mittee a series of trenches was dug and some fossils collected which were de- 

 termined by Mr. F. R. Cowper Reed and assigned by him to the Llandovery. No 

 tuffs were met with in the area to the S.E. of the Moon's Hill quarry, the pre- 

 valent rock being a somewhat sandy mudstone. The results obtained were 

 published in the report of the above Committee presented at Dublin in 1908. 



During the present year further excavations have been carried out leading 

 to the discovery of large additional series of fossils, which bring Mr. Reed' to 

 the conclusion that the sandy niudstones in the area to the S.E. of the Moon's 

 Hill quarry are of Wenlock rather than Llandovery age. It has also been ascer- 

 tained : — 



(1) That the dip of these Wenlock rocks is far greater than that of the 

 neighbouring Old Red Sandstone, rendering a conformable passage from Silurian 

 to Old Red Sandstone improbable. No trace has been found of a Ludlow fauna. 



(2) That the dip of the Wenlock rocks is such that they clearly overlie the 

 andesite of Moon's Hill. The general succession of Silurian rocks in the Eastern 

 Mendips is therefore as follows : — 



Mudstone often very fossiliferous, with subordinate 



bands of highly micaceous sandstone exposed in the 



Wenlock -I rail cuttings and by trenching in the fields to the 



S.E. of the Moon's Hill quarry. Thickness not 



ascertainable. 



Pyroxene andesite of Moon's Hill, Sunnyhill, and 

 Downhead quarries. In each case some tuff is inter- 

 bedded with the andesite. Thickness probably not 



less than 500 ft. 



j , , f Tuff, coarse and fine, exposed in Sunnyhill quarry 



y \ and by trenching at Tadhill and Downhead, about 110 ft. seen 



No further information has been obtained regarding the peculiar ' coarse 

 ashy conglomerate ' referred to in the above papers. 



