190 - 4 .] Mr J. G. Goodchild on Intrusive Rocks. 203- 
wedge the dolerite is seen, as in the last case cited, to have eaten 
its way into the rock, across joints and faults as well, without any 
signs of disruption. 
Fig. 3 shows the top of the dolerite in the old quarry at the 
north end of Salisbury Crags. The dolerite in this case has made 
its way upwards into the Cornstones there in a very irregular 
manner, and has consequently left a downward extension or tongue 
of sandstone (now altered into a quartzite) with the intrusive rocks 
on either side of it. The figure, traced from a photograph by Mr 
Fingland, of the Glasgow University, shows irregular tongues of 
the dolerite in the sandstone, which have evidently made their 
way there without causing the least mechanical disturbance. Two 
or three cases are seen in this example in which the dolerite has 
tunnelled into the sandstone, and has left an unbroken ring of the 
sandstone around. At the bottom right-hand side are included 
fragments * of the country rock still remaining undissolved within 
the dolerite. The section at the foot of Salisbury Crags described 
by Hay Cunningham (op. cit.), and figured on Plate IV. of his 
Geology of the Lothians , is one of very considerable interest in the 
present connection. One aspect of it is represented on fig. 4, 
traced from a photograph by Mr Stenhouse. It shows several 
tongues of dolerite ending off against unbroken country rock 
(Cornstones). With these finger-like processes there are several 
protrusions of dolerite completely surrounded by the unbroken 
sandstone. One example of this has been detached, and is now 
exhibited in the Gallery of Scottish Geology and Mineralogy in 
the Edinburgh Museum of Science and Art, along with other 
examples to he referred to in detail presently. On the south side 
of the Queen’s Park alone nineteen cases of dolerite, either ending 
off against unbroken rock, or else completely surrounded by it, 
have already been noted, and there are probably many others 
there, as well as more in other parts of the Park. In Hay 
Cunningham’s treatise (op. cit ., PL III. fig. 1) is an example of 
the same kind occurring at the base of the intrusive basalt of St 
Leonard’s Hill. Again, there are masses of sandstone caught up 
in the curious dyke-like mass of dolerite which rises into the rock of 
Salisbury Crags from below the Kadical Koad, near its western- 
* Why should these be called Xenoliths ? 
