w 



84 



LIAS LIMESTONES, 



Wall-case 



gYllIry. Though dug from a pit at a very short distance from that 



• ' from which the preceding specimen (No. 100) was procured 

 ' this chalk does not prove equally beneficial as a dressing 

 for land. 



102. — Earthy limestone, the equivalent, probably, of 



Uj)pe 



tf 



103. — Red chalk, earthy red limestone, probably equi- 



valent to the Gault. 

 104. 



rft 



105. — Marlstone, argillaceous limestone, from the Lias 

 containing shells and the broken stems of Crinoids. — From 

 foundered blocks on the sea shore between Down Cliff and 

 Thorncombe Beacon, Dorset. Map 17. 



106. — Lower lias, argillaceous limestone, with numer- 

 ous fossil shells, with the valves united, showing the 

 gaping position in which, after death, the shells lay filled 

 with calcareous mud in the sea bottom. Sec p. 39. — Four 

 miles south of Gloucester. 



107. — Lower lias, argillaceous limestone, with Lima, 

 Oysters, and other fossils. — Freathern Cliff, near Newnham, 

 Gloucestershire. 



108. — Lias, polished slab of argillaceous limestone. 

 From its occasionally curiously marked appearance bearing 

 a rough resemblance to ruins and trees, this limestone is 

 sometimes called "ruin or landscape marble," and some- 

 some times " Gotham marble " from its occurrence at that 

 place in the neighbourhood of Bristol. It is found in thin 

 layers in Lias Clay. 



109. 



Lias, argillaceous limestone, containing Oysters. 



Two miles east of Newport, Monmouthshire. 



The blue Lias Limestones generally contain a good deal 

 of clay, and are eminently useful as hydraulic lime, setting, 

 it is said, better under water than the lime made from most 

 other limestones. 



110. — Lower or " white lias," argillaceous limestone, 

 near the base of the Lias, with layers of bivalves (Avicula 

 decussata), immediately overlying the bone bed, "Wall" 



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