1818.] Proceedings of Philosophical Societies. 137 



consists of beds of conglomerate, of red sandstone, and of a red 

 and greenish grey indurated marl, in which rock salt and brine 

 springs are usually found. 



On the north of the red sandstone, and occupying the prin- 

 cipal part of the coast from Minehead to the mouth of the Parret, 

 occur beds of lias limestone. The junction of the red sandstone 

 and lias is very apparent on many parts of the coast ; but such 

 is the disturbance and mutual intermixture of these rocks, that it 

 is by no means easy to obtain a satisfactory proof of their relative 

 superposition with regard to each other. The upper beds of the 

 lias are of a light blue colour, which, by calcination, or long 

 exposure to the atmosphere, passes to a yellowish buff colour : 

 the lime which they produce is not in much estimation for agri- 

 cultural purposes, but has the valuable property of forming a 

 cement, which sets under water. The limestone of the lower 

 beds of the lias is of a much darker colour, is very fetid when 

 rubbed or struck, and yields a lime in great estimation as a 

 manure. 



The lamellar blue clay, which alternates with the beds of lias, 

 incloses lenticular concretions of clayey limestone, many of 

 which when broken present the structure of septaria, the sparry 

 ■ matter of the veins being in some instances calcareous spar, in 

 Others sulphate of strontian, occasionally in well defined crystals. 



The red sandstone on the coast west of Watchett contains 

 much gypsum, inclosing grains of sand and small pieces of 

 quartz ; but no rock salt has hitherto been observed in it. 



Three miles west of the mouth of the Parret the coast consists of 

 deep and almost fluid mud, containing many trunks and branches 

 of trees, of which some of the former still retain their natural 

 position. Much of the timber has of late years been carried off 

 by the neighbouring inhabitants for fuel and other purposes. 

 How far this submarine forest extends to sea is unknown. 



III. — 10. Description of a Clinometer. By the Right Hon. 

 Lord Webb Seymour, F.R.S. &c. 



The description of this instrument for measuring the inclina- 

 tion of strata cannot be understood without the accompanying 

 plates. 



{To be continued.) 



Article XVI. 



Proceedings of Philosophical Societies. 



GEOLOGICAL SOCIETY. 



May 15. — The reading of a paper, by Thomas Weaver, Esq. 

 " On the Geological Relations of the East of Ireland," was 

 commenced. 



June 5. — The reading of Mr. Weaver's paper was continued. 



2 



