404 G. Sickling — Old Heel Sandstone of Forfarshire. 



and more persistent, is a fair description of the whole deposit. In 

 a broad view, the whole mass would be described as a conglomerate. 

 No trace of calcareous material is present, except in the form of veins 

 and patches of calcite (e.g. about Whiting Ness). These veins are of 

 value as indicating that there have formerly been calcareous strata 

 overlying these beds, as would be expected from a comparison with 

 the deposit in other areas, 



I have carefully searched through the pebbles in the conglomerates 

 for evidence on the age of these rocks, but with onlj^ negative results. 

 There appear to be no pebbles of later age than the Lower Old Red, 

 and this fact so far confirms the Upper Old Red age of these beds. 



In the other two exposures of this series of rocks on the coast, viz. 

 at Boddin Point and St. Cyrus, the lower part of the section shows 

 red sandstone, the upper cornstone. At Boddin Point the series is 

 brought down by a strong fault against the porphyrites, the fault 

 being beautifully exposed on the south side of the headland. About 

 40 to 50 feet of quite soft yellow or white sandstone, mottled 

 with light red, is exposed below the cornstone, while the base of the 

 series is thrown below sea-level. Above this sandstone we have the 

 following beds, No. 1 being the sandstone itself: — 



Feet. 



(11) Hnrd brecciated very calcareous sandstone +4 



(10) Mottled purple sandstone 1 



(9) Hard compact calcareous sandstone ... ... ... ... 2 



(8) Fine soft mottled purple sandstone, with irregular limestone 



nodules 3 



(7) Mottled purple sandstone ... 4 



(6) Yellow brecciated sandstone, with dendrites 5 



(5) Mottled yellow and red sandstone... ... ... ... ... 10 



(4) Brecciated yellow dolomite, with dendrites ... ... ... f 



(3) Mottled sandstone 4 



(2) Yellow dolomite, with dendrites ... ... ... ... ... 1 



(1) Yellow and mottled sandstone +40 



The terms used in the above table are the best I could find to 

 briefly indicate the nature of the various beds, but accurate description 

 is exceedingly difficult. As to the nature of the materials composing 

 the rocks, every mixture may be found between a pure sandstone and 

 an almost pure limestone, as I have ascertained by actual estimation 

 of the quantity of lime in various specimens. And as to the structure 

 of the rock, there is still further difficulty. All the beds described as 

 ' brecciated ' have the appearance of typical breccias on a weathered 

 surface, but on a fresh fracture the same rock frequentlj^ appears 

 perfectly compact and even. In such cases I believe the brecciated 

 appearance is entirely due to crystallisation in the limy matrix. In 

 other cases the brecciated character is still evident, though far less 

 prominent, on the broken surface, and in those instances it would seem 

 to be due to the breaking up and re-consolidation of the deposit 

 during its formation. Very seldom is the material a true breccia. 

 Here and there, however, pebbles in one bed have evidently been 

 derived from the break-up of a lower stratum. Irregularity and 

 discontinuity of deposit are further evidenced by strongly developed 

 false-bedding, by local erosion of beds (No. 6, for example, is in 



