270 The Irish Naturalist. November, 



ON THE MARINE FAUNA OF THE BOULDER CLAY. 



BY JOSEPH WRIGHT, F.G.S. 



He had examiued microscopically 112 samples of Boulder clay from 

 various places in the British Isles and in Canada ; 47 of these were from 

 Ireland, 27 from England and Wales, 22 from Scotland, i from the Isle 

 of Man, and 14 from Canada. In 71 of the British and 9 of the Canadian 

 samples Foraminifera were found. The specimens of the clay had been 

 taken from various altitudes, some few of them from localities over 1,000 

 feet above the sea. Almost all the forms found were referable to species 

 which at present lived at moderate depths off our coast, and most of 

 them had the fresh appearance of these species. Nonionina depressula was 

 often met with in great profusion, fully one-half of the entire specimens 

 found being referable to this species. One hundred and thirteen species 

 had been found in the clays of Ireland, 72 of those in the Isle of Man, 66 

 in England and Wales, 40 in Scotland, and 15 in Canada. In 31 of the 

 gatherings no Foraminifera were met with, whilst in some of the others 

 they were very rare. The absence or the scarcity of specimens in some 

 of the samples might be due, in part at least, to the circumstances that 

 it was only the first floatings from the clays that were examined, and 

 also that these minute organisms were liable at times to be overlooked 

 when the material was being examined. To ascertain how far floatings 

 could be relied on for giving conclusive results, loz. troy of the Boulder 

 clay from Woodburn, near Carrickfergus, was examined with the utmost 

 care. The first floating was found to contain 1,400 specimens, the floating 

 process being repeated twenty-five times before specimens ceased to come 

 up ; upwards of 600 additional specimens were thus obtained. What re- 

 mained of the clay was then examined in detail with the microscope, 

 and 67 more specimens were got from it. In the Boulder clay at Knock 

 Glen, near Belfast, 79 species were obtained, many of them being very 

 rare forms, 6 being only known as recent British species from collections 

 on the west coast of Ireland, two of these also occurring off the west coast 

 of Scotland. The presence of these microzoa would lead them to infer 

 that the clay at this place was probably deposited in deep water, when 

 the land stood at a much lower level than at present, and when the 

 marine conditions must have been somewhat similar to what now pre- 

 vails off the west coast of Ireland. At Woodburn, near Carrickfergus, 

 the clay was very similar to that at the Knock Glen, being very fine and 

 comparatively free from stones. Here also three of the west of Ireland 

 foraminifera occurred, also an exceptionally large specimen of Cornu- 

 spv-a involvens. It was many diameters larger than any specimen seen by 

 the author from recent British gatherings. In size it closely resembled 

 an allied form of Coniuspira carinata^ taken in dredgings off the west of 

 Ireland. Some of these west of Ireland forms have also been found 'in 

 Boulder clay at other places. Lagena fimbriata was found at five other 

 localities besides those of Knock and Woodburn, one of these being at 

 Larch Hill, County Dublin, 800 feet above the sea, and Polystomella 

 stibnodosa was got in Ayrshire at 1,071 feet elevation. 



