350 Mr. Weaver's Geological Observations on 



I have no where perceived any vestige of organized bodies in the new^ red 

 sandstone formation. 



c. Third sedimentary Series. 



§ 28. Of this series, in which are comprehended the formations of lias and 

 oolite limestone, of iron and green sandstone, and of chalk, the first two only 

 are found in this district; consisting of beds of compact, sandy and oolitic 

 limestone, in association with beds of clay, marl, and sand ; the compact 

 argillaceous limestone bearing, as is well known, the name of lias. 



§ 29. The general characters and relations of the lias limestone, as ex- 

 hibited in the south-western part of Somersetshire, and in the north-east of 

 Ireland, have been described in the very valuable papers on those tracts re- 

 spectively, by Mr. Horner, and by the Rev. W. D. Conybeare and Professor 

 Buckland, in the third volume of the Geological Transactions *. Its relations 

 may also be studied to advantage, somewhat beyond the limits of the district 

 included in the map (Plate XXXIX.) at Pyrton, and at Ingatestone Common, 

 on the road between Wickwar and Hawkesbury Upton. Its relative position 

 at those places, with respect to other formations, has been already noticed 

 (§ 6. and § 10.). At Ingatestone Common, the lias limestone is interstratified 

 with blueish clay-marl and slaty-clay-marl, which are exposed to the depth of 

 twenty or thirty feet, in the brook near the boundary of the parishes of Wickwar 

 and Hawkesbury. The upper beds, in which those of the clay-marl predomi- 

 nate, abound in ammonites, ostracites, gryphites, pectinites, &c. ; while in 

 the deepest bed of limestone here visible, which is about one foot thick and 

 reposes on blue clay-marl, some fish bones may be occasionally observed. 

 The limestone is much intermixed with hornstone and flinty matter. Nearer 

 towards Wickwar, the lowest bed of the lias formation is found resting on the 

 new red clay-marl ; and it there contains numerous fragments of bones, 

 forming a kind of conglomerate analogous to the osseous bed that occurs in 

 the lower part of the lias, in Westbury and Aust cliffs on the banks of the 

 Severn. 



At Pyrton, on the left bank of the Severn, where the lower beds of the 

 lias formation appear, the limestone greatly predominates, alternating with 

 thin beds of blue clay and clay-marl, and extending some distance up the 

 river ; but still further upward the latter beds prevail. Near Pyrton, I ob- 

 served the following organic remains : of chambered univalves, ammonites, 

 nautilites, belemnites ; of univalves not chambered, trochites ; of bivalves 



* The lias of England in general has been described, more fully, by the Rev. W. D. Cony- 

 beare, in the Outlines of the Geology of England and Wales, 1822. 



