32 C.C. NATURAL HISTORY SOCIEl'Y. 



mountainous edges, and the dome shaped mass of May Hill, which 

 being crowned with a clump of firs is easy to mark, have no 

 corresponding hills in the Cotteswold range, and this difference in 

 appearance is accompanied by, and is in truth due to, a difference in 

 the rock material of which they are built. The Malverns are made 

 up of crystalline rocks, which have been heated to the melting point, 

 and then crystallised out, and are amongst the very oldest rocks in 

 our Islands. The name Archean has been given to them. Down 

 the whole of the Eastern side of the Malverns runs a great earth 

 crack. And now beds of red sandstone formed many long ages after 

 the rocks of the Malverns rest against those hills. These slope 

 gradually towards Leckhampton Hill, are covered about half way 

 across the Valley by Lias clays, a few feet of White Lias, as it is 

 termed, intervening, and these Lias clays continue to the foot of 

 Leckhampton Hill, where they, in their turn are covered by the 

 Oolite Limestone. 



But to the South of the Malverns occurs another set of beds 

 which lie beneath the red sandstone, and these are termed the 

 Silurian beds, and are composed of limestones and sandstones, and 

 May Hill is carved out of these. Some of these limestones are 

 extremely fossiliferous, but their fossils are very different from those 

 found in the limestones of Leckhampton, for the animals which lived 

 in them existed many thousands of years before the Leckhampton 

 beds were formed, and when the latter were laid down had entirely 

 ceased to exist. No doubt in time now long gone by the Leckhamp- 

 ton Hill beds extended much further West possibly over the Malverns, 

 but the rivers and the rain and the frost has gradually cut them back 

 Eastwards and the hard Oolite cracking and dissolving much more 

 easily than the thick clay on which it rests has been worn back so as 

 to form more or less of an inland cliff, which goes by the name of an 

 escarpment. This clift we see now running from Cleeve Cloud, behind 

 Battledown, to Leckhampton Hill, and away South past Gloucester. 

 And even now it is being worn back little by little, though so 

 gradually that none of us can see it going on. But every rainy day 

 swells the brooks and streams that come down to the plain, and they 

 get a yellow colour because they are bringing down from the hills little 

 pieces of rock and are carrying them down and away from the hills. 



