252 ME. T. CODEINGrTON ON SUBMERGED ROCX-YALLErs [Aug. 1 898, 



mouth of the pill (fig. 1), where the deepest part of the valley is 

 45 feet below the level of low-water spring-tides, and is filled with 

 mud and silt to a depth of 44-50 feet. At the mouth of the pill 

 the rock was not traced to the deepest part of the section, but just 

 beyond, and outside the pill a complete section was made in which 

 the rock-valley beneath the 



Pig. l.—Neyland Pill. 



[Scales: Horizontal, 400 feet=l inch. 

 Vertical, 100 feet=l inch.] 



mud is well marked, the 

 deepest boring being 45 feet 

 below the level of low-water 

 spring-tides through 22 feet 

 of silt. 



J^ot far from the mouth of 

 the pill there is a depth of 

 QQ feet in the main channel 

 of Milford Haven. 



The rock-bottom and sides 

 of the pill are of Old Eed 

 Sandstone, and there is the 

 same general outline of cross-section above and below the present 

 water-line. The sides have slopes of 1 vertical to 2-|, 2|, and 

 1^ horizontal. The late Mr. Okeden, who made the borings, found 

 Diatomaceae in the clay brought up by the boring-tool, and he 

 preserved and mounted many specimens, now unfortunately lost. 



About 4 miles lower down the Haven is Milford, where docks 

 have been constructed at the mouth of a pill, similar in general 

 features to ISTeyland Pill. 

 Fig. 2 is a section across the 

 mouth of the pill, as revealed 

 in the progress of the dock- 

 works. The bottom of the 

 rock-valley is 51 feet below 

 the level of low-water spring- 

 tides, and had 58 feet of mud 

 •over it. Farther out, at low- 

 water mark, the depth to the 

 rock was found to be 65 feet, 

 with that depth of mud over 

 it. The rock, as at Neyland, 

 is Old Red Sandstone. 



Fig. 2. 



Milford Docks 

 Section through Entrance Lock. 



H. W. 0. S. T. 



[Scales : Horizontal, 400 feet^l inch. 

 Vertical, 100 feet=l inch.] 



The length of the main stream flowing into JS'eyland Pill is about 

 6 miles, draining about 10 square miles of country. That flowing 

 into Milford Pill is some 3 miles long, draining an area of about 6 

 square miles. Both streams originate in ground about 300 feet 

 above the sea-level. 



The deepest sounding in Milford Haven, opposite Milford, is 72 feet 

 below the level of low water, and there is no deeper sounding down 

 to the entrance of the Haven. The 10-fathom line of the chart runs 

 across the mouth, with a loop extending up the Haven, and there are 

 many rocks inside this line. Outside it the 20-fa thorn line is less 



