206 BATHYMETRICAL SURVEY OF 



of arenaceous Foraminifera. The mica is present in extremely minute 

 flakes, and imperceptible to the naked eye in the unwashed material. 

 In this respect the material from Loch Morar differs from that obtained 

 in most of the other lochs, in the samples from which the glistening 

 mica flakes attract one's attention. 



Loch Beoraid (see Plate XLIV.). Loch Beoraid is a long narrow 

 loch, lying amidst wild and rocky scenery about 3 miles to the south of 

 Loch Morar. There were no Ordnance Survey bench-marks available 

 in the vicinity of the loch from which the level of the water surface 

 could be ascertained, but, from the position of the spot-levels, the height 

 was estimated at 168 feet above the sea. The loch trends in an east-to- 

 west direction, and is fed by numerous small burns, the largest, Allt a 

 Ghlinne Dhuinii, flowing in at the east end. The Meoble river, which 

 drains the loch, issues at the west end, and, after a course of 3 miles, 

 falls into Loch Morar. There are one or two small islands at the east 

 end of the loch, and one large one lying in the centre, almost equidistant 

 from both ends of the loch. The length of Loch Beoraid is 3J miles, and 

 its maximum breadth about one-third of a mile ; the mean breadth is 

 one-sixth of a mile, and the area covered by water is 352 acres, or over 

 half a square mile. The number of soundings taken was 120, the 

 maximum depth obtained being 159 feet; the mean depth is over 72 

 feet. The volume of water is estimated at 1,156,000,000 cubic feet, 

 and the drainage area extends to 7680 acres, or nearly 12 square miles. 



There are two basins over 100 feet in depth ; one at the west end of 

 the loch three-quarters of a mile in length, with a maximum breadth of 

 one-sixth of a mile, approaching to within one-eighth of a mile from that 

 end. The maximum depth obtained in it was 147 feet, comparatively 

 very near the outflow. The eastern basin is nearly 1J miles in length, 

 with a maximum depth of 159 feet, the area over 150 feet in depth being 

 almost half a mile in length. The 50-feet area is continuous from end 

 to end, passing to the south of the large central island, the depth in the 

 channel being 53 feet. Loch Beoraid is a rock basin divided into two 

 separate basins by a rocky ridge which crosses the loch at the large 

 island. At the west end of the loch there is a rocky barrier, and the 

 river Meoble in its course forms a waterfall over rocks a short distance 

 from its exit. The loch was surveyed on July 1, 1902. 



Temperature Observations. The following series of temperatures 

 was taken about a quarter of a mile from the west end of the loch : 



Surface 60'0 Fahr. 



10 feet 59-8 ,, 



25 ,, 53'9 ,, 



50 51-0 



100 , 47'5 ,, 



140 , 48 -0 



