Trof. T. B. Jones — Geology of Kingsdere Valley. 513 



Eecurring to the evidences of the archiing or dome-structure of 

 strata over the area of the Kingsclere Valley, Professor Jones in- 

 sisted on the importance of the evidences seen in chalk-pits and 

 other excavations, where the sections show that the strata incline, or 

 "dip " away north or south, or in other directions, as the case may 

 be ; and he referred to the value of stratification in elucidating the 

 history of the earth's crust. The uprising and the washing away of 

 twelve, twenty, or hundreds of square miles of upraised strata, even 

 a thousand or more feet in thickness, has been of relatively common 

 occurrence, when we look over the world geologically ; for many 

 such hollow areas, or " inliers," have been swept clean, of the broken 

 ■upper layers of an " anticlinal " fold of crumpled strata. Another 

 such " valley of elevation " lies six miles to the north-west, along 

 the Hampshire Hills, where Ham and Shalborne are built on similar 

 " Greensand ;" and still further west, the Vale of Pusey, of still 

 larger dimensions, indicates the continuance of the line of elevation 

 towards the Bristol area. On the south-west also a similar and 

 parallel line of uplift has exposed the beds beneath the Chalk in the 

 picturesque Vale of Wardour ; and on the south-east, in the extensive 

 and interesting Valley of the Wealden, including the Wealds of 

 Kent, Surrey, and Sussex. The destruction of so much rocky 

 material as that not only which, in the form of continuous strata, 

 connected the side-hills of the valleys, but which also had once ex- 

 isted to a great height above the present surface of the plateaux, is a 

 subject of serious geological thought. That the land was below the 

 level of the sea, as a sea-bed, must be remembered ; and, though 

 once in a way the sea may have been accumulated to an extra height 

 in this or that part of the world, yet, as a rule, the rising of the sea- 

 beds from beneath the sea is owing to crumplings of the earth's 

 crust, from contractions, as the layers in a great roll of cloth or linen, 

 when crushed and folded by side pressure, rise up above the general 

 level ; and if such ridges of the crumpled cloth were pared down, as 

 the curved strata have been by the waves and currents of the sea, 

 the lower layers would be exposed, and, if soft, would be still more 

 deeply worn away. Further, this destruction, or rather removal, of 

 the upper beds, and the exposure of the lower by " denudation," 

 would be continued, if not enhanced, by the action of snow, frost, 

 ice, rain, and torrents, when the land rose higher and higher. Such 

 work we see is going on around us, even on a common rainy day ; 

 and much more active are these agents of nature in the tropical and 

 the arctic regions respectively. And there was a time not long ago 

 geologically, though at least ten thousand years since, when an arctic 

 climate was succeeded in these regions by a time of snow and rains, 

 called the '■' Pluvial Period " by Mr. Alfred Tylor, to which the old 

 broad valleys and gravel-beds of our rivers and many other features 

 of this country bear witness. 



Eegarding the continuity of the Chalk with the other great strata, 

 — it forms the country south of Ladel Hill to right and left, with a 

 diminished thickness, compared with its original condition, and with 

 the loss of all the once overlying Tertiary beds, as far as the confines 



VOL. VIII. — NO. LXXXIX. 33 



