1873.] JUDD THE SECONDARY ROCKS OF SCOTLAND. 193 



of the mass is not quite so perfectly seen as in the last instance ; but 

 it is probably upwards of 40 feet long, and at least 20 feet thick. 

 In the exposed section on the south side of Dunglass (the Green 

 Table) there may be seen, as indicated in tbe sketch (fig. 5, p. 121), 

 several large included blocks ; one of these is about 10 feet long and 

 4 feet thick. 



(c) Position. — The position of the blocks in the mass is as various 

 as their form and size. In some cases, like those of the great blocks 

 just noticed, the included masses are seen standing on end, with their 

 stratification vertical. In no case does there appear to be any sort- 

 ing of the materials, which are found heaped together in the wildest 

 confusion, angular and subangular blocks, pebbles, trunks of trees, 

 stems of cycads, masses of coral, shells, shell-detritus, sand and 

 mud. 



(d) Markings. — It may be readily imagined that one of the first 

 channels into which the observations of a student of this singular 

 phenomenon would be directed, in order to detect the cause of trans- 

 port of these blocks, would be the search for evidence of the action 

 of glacial or floating ice, in the now well-understood and easily re- 

 cognized polishing, scratching, and grooving which ice-borne rocks 

 usually exhibit. But although innumerable opportunities are af- 

 forded for observing the surfaces of the blocks, many of which have 

 evidently not been in the least degree waterworn before being in- 

 volved in the surrounding and protective matrix, and although I 

 was on the constant look-out for evidence of glacial markings through 

 many weeks during which I studied these beds, yet it must be con- 

 fessed that in no single instance was I able to detect a clear and in- 

 disputable example of any such markings. 



{e) Material. — The rocks included as fragments in the " brec- 

 ciated beds " are somewhat various, consisting principally of cal- 

 careous flagstones, often highly micaceous, and exhibiting all the 

 characteristic features of the Caithness Flags of the Middle Old lied 

 Sandstone, with hard sandstones, and indurated, often variegated 

 shales. Occasionally I have found masses which I have been dis- 

 posed to refer, though with some doubt, to the Silurian strata 

 (altered flagstones) of the district ; but blocks of granite or of the 

 conspicuous Old Red conglomerate of the district are, as far as my 

 own observations and those of Sir Roderick Murchison go, altogether 

 absent from the " brecciated beds." 



(/) Fossils. — Hugh Miller was, as already intimated, the first to 

 detect fossils in the included blocks of the " brecciated beds." He 

 records that he found Osteolejns and Old-Red-Sandstone fucoids in 

 them ; and his testimony, in a matter of this kind, will be admitted 

 to be the most weighty and satisfactory which could possibly be ad- 

 duced, when we consider the very intimate and exact knowledge 

 which he possessed of the Old Red Sandstone strata of the North of 

 Scotland. His observations I have been able to confirm by the dis- 

 covery in the blocks in question of very numerous fragments of the 

 Old-Red fishes, preserved in the same manner as is usually the case 

 in the Caithness Flags. Many of these fragments are too small to be 



VOL. XXIX. r-ART I, O 



