486 KEi'OET — 1893. 



of stratification are visible. No organic remains have been found in thia 

 deposit. 



3. The Shelly Clay. — The highest part of the shelly clay near the 

 soibth.east end of the ' main pit ' is 503^ feet above sea-level. From the 

 levels taken in 1882, when a small excavation was made by Mr. Fraser, 

 the height of the shelly clay at the front of the west end of the 

 present ' main pit ' was 501 feet. The top of this deposit where visible 

 rises slightly towards the east or south-east to the extent perhaps of 

 1 foot in 20 or 25 feet. 



The shelly clay as exposed in the ' main pit ' varied from 14 to 16 feet 

 in thickness. It is a tenacious clay or silt of a blue dark grey colour, 

 save the lowest 2 feet, where the tint is brownish grey. At this lower 

 level there is an admixture of fine gravel. The boundary line between 

 the shelly clay and underlying gravel is clearly defined. There is no 

 intermingling of the two deposits. 



There are slight traces of stratification in the blue clay. At a depth 

 of 3^ feet a horizontal line was observed in the deposit after exposure for 

 several days to heavy rain, but scarcely any part of this line could be 

 traced when a fresh surface was revealed. At a depth of 6^ or 7 feet, 

 horizontal streaks or thin layers of sand or fine gravel occur, but not in 

 continuous layers. 



It is also important to note, as throwing light on the origin of the 

 deposit, that the silt was traversed at certain levels by annelid burrows, 

 more or less vertical, the tracks being darker in colour than the sui'- 

 rounding silt. The burrows in most cases were laterally compressed. 



Of special interest also is the occurrence of a series of nearly vertical 

 cracks or fissures traversing the clay in a uniform direction, viz., north- 

 west and south-east, the tops of the fissures being bent towards the 

 north-east. An attempt was made to photograph these fissures or cracks, 

 which formed a conspicuous feature in the deposit. 



The upper 12 feet of blue clay is almost free from stones ; those 

 which do occur within these limits vary from the size of peas ta 

 1^ inch in diameter as a rule. But they become more numerous and 

 slightly larger at a depth of about 6 feet. In this upper portion they 

 are nearly all well-rounded and of the harder varieties. The lowest 

 3 or 4 feet of the deposit (especially the lowest 18 inches) contains a 

 larger proportion of stones, varying in size from peas to 2 inches across, 

 and almost all well-rounded. 



At a lower depth than 6 feet a few stones of a larger size than the 

 foregoing dimensions were found, the largest varying from 3 to 6 inches 

 across, some being well-rounded and some subangular. The largest 

 stone met with in the blue clay, measuring 9 inches by 7 inches by 

 4i- inches, consists of dark micaceous gneiss : it is partially rounded, 

 ice-grooved on one side, and with the mark where a balanus had been 

 attached on one end of the grooving. Two small stones with several 

 nearly entire balani were found at the very bottom of the shelly clay at 

 the south-west end of the pit. 



During a subsequent inspection of the ' main pit ' two small striated 

 stones of fine-grained sandstone were observed in the lowest 6 feet of the 

 deposit ; and about the same level, two rounded stones (4 inches by 

 3 inches) with fresh ialanus marks. 



Only three striated stones were met with in the shelly clay, the 

 general well-rounded chai'acter of the stones and the absence of st na- 

 tions being a striking feature of the deposit. 



