67 



sea, were buried in the mud, fossilized at the spot, and exposed 

 through the removal of the covering clays by the action of the 

 ordinary agents of denudation. 



The period subsequent to the one described above — the Upper 

 Eocene — is still somewhat enveloped in obscurity owing to the 

 absence or non-discovery of undoubtable characteristic fossils 

 appertaining to the respective deposits. It appears to me that 

 a considerable interyal must have elapsed between the depo- 

 sition of the grits, as the last of the Eocene, and the " Ardros- 

 san (or mottled) clays" and gravels, the succeeding deposits of 

 the following, more recent era, because, even assuming a very 

 rapid jDctrification of the loose debris into real stone under the 

 influence of silicated hot waters, yet some considerable time 

 must elapse before successive layers are transformed so com- 

 pletely as we find the " Turritella grits." Yet we find even in 

 the lowest accessible layers of these more recent deposits frag- 

 ments of the former, with their unmistakeable fossils, differing 

 in nothing from those obtained in situ. Very probably, there- 

 fore, these grits were overlaid to some extent by looser materials, 

 assisting through pressure m transforming them into stone. 

 The whole was then elevated above the sea-level, from about 

 the southern boundary of Cunningham, and northward through 

 the whole hundred and further, so as to enable the waves to 

 gnaw away a large portion of those (then recent) deposits, and 

 rearrange them near shore in shallow disturbed waters, in the 

 manner exhibited by the modern sea-cliffs about Ardrossan. 

 The largest proportion of the gravels accompanying them 

 being made up of fragments of all kinds of locally-occurring 

 rocks in all stages of wear, from sharp-angled ones to the 

 globose jDcbble, it seems certain — 1. That they were not 

 brought any great distance ; and 2. That, false bedding being 

 observable at odd spots in all elevations, they w^ere deposited 

 in a shallow turbulent sea near shore. This elevatory move- 

 ment may have been coeval with the activity of the south- 

 eastern volcanoes, or more likely have preceded this, ere the 

 pent-u]) gases found an outlet through them. This would fix 

 the event about the close of the Pliocene period, to which con- 

 clusion also the occurrence of small patches of the desert 

 sandstone (or ferruginous comglomerate) points, the greater 

 part of the latter having been removed by denudation locally 

 during subsequent periods. However, this elevatory movement 

 cannot have been long geologically speaking, else the compara- 

 tively inconsiderable Eocene dejoosits would have been much 

 more reduced, considering their very incoherent structure, and 

 was again succeeded by submergence to such extent that not 

 even the smallest hill-top escaped ; for everywhere, even upon 

 the (locally) most elevated summit we find indications thereof 



