366 IGNEOUS GEOLOGY OF THE BATHGATE AND LINLITHGOW HILLS, 
east of Wairdlaw, and another at Haddie’s Walls in the Kipps coalfield. The small 
dyke piercing the lava-cliff to the west of Hiltly is probably of contemporaneous origin. 
Much also of the intrusive rock in the vicinity of Ochiltree Mill, as well as the Walton 
and Carriden intrusions, may be referred, from petrographical characters, to the first 
period of igneous activity. 
(b) The later intrusions.—These may be subdivided into two groups :— 
1. Dyke-like intrusions with a vertical or highly inclined junction— 
E.g. The Raven Craig, the Knock, the Witch Craig, the Wairdlaw and 
Cockleroy intrusions, and the H.—W. dykes. 
2. Sills or laccolitic intrusions— 
E.g. The Kettlestoun Hills, the Belsyde Hills, and the Torphichen 
Hills. 
The similarity in petrographical type of these intrusions indicates contemporaneity 
of origin in late or post-carboniferous times. Strict contemporaneity, however, is not 
implied, the intrusions having evidently been inserted in succession during the period. 
Those intrusions with a N.-S. elongation are probably oldest, being cut, as in the case — 
of the Raven Craig, by the E.—W. faults, along which dykes have usually risen. These 
dykes are apparently the feeders of the sills, the lowest and oldest of which are some- — 
times covered by the feeders of the higher and younger. The upper limits of the dykes — 
themselves were probably irregular, different portions of the same dyke rising to 
different levels. The upward termination of one of these dykes is particularly well — 
seen at Broomyknowes and Belcraigs. ‘This may explain in part the discontinuity of — 
outcrop of some of these dykes when traced from east to west. In other cases, how- 
ever, as in the Parkly Craigs dyke, the different portions seem to run out, the dyke 
being continued on a parallel line a few yards to the north or south. 
GENERAL RESULTS. 
L. The lavas of the Bathgate Hills are olivine-bearing from base to summit of the 
series, and are pierced by a few contemporaneous intrusions of similar material. 
2. The Bo'ness lavas form a group entirely distinct from the lava-zones of the 
Bathgate Hills. 
3. The volcanic zones are crossed by a later-connected series of dykes and sills, 
probably of Palzeozoic age. | 
The detailed results of the microscopical and chemical analysis of the rocks are 
reserved for a future paper. 
