The waters of the Ythan, the Ugie, and the Don are frequented by fresh-water mussels which produce pearls. These grow best on a pebbly bottom not too deep and are 3 to 7 inches long and 1-1/2 to 2-1/2 broad. The internal surface is bluish or with a shade of pink. The search for these mussels in order to secure the pearls they may and do sometimes contain was once a recognised industry. To-day it is spasmodic and mostly in the hands of vagrants. Many beds are destroyed before the mussels are mature and this lessens the chances of success. The pearl-fisher usually wades in the river, making observation of the bottom by means of a floating glass which removes the disturbing effect of the surface ripple. He thus obtains a clear view of the river-bed, and by means of a forked stick dislodges the mussels and brings them to bank, 150 making a good day’s work. He opens them at leisure and finds that the great majority of his pile are without pearls. If he be lucky enough, however, to come upon a batch of mature shells he may find a pearl worth £20. As a rule the price is not above ten or twenty shillings. Much depends on the size and the colouring. The most valuable are those of a pinkish hue. 8. Round the Coast. The harbour-mouth, which is also the mouth of the Dee, is the beginning of the county on the sea-board. It is protected by two breakwaters, north and south, which shelter the entrance channel from the fury of easterly and north-easterly gales. To the south, in Kincardineshire, is the Girdleness lighthouse, 185 feet high, flashing a light every twenty seconds with a range of visibility stated at 19 miles. To the north of the harbour entrance are the links and the bathing station. The latter was erected in 1895 and has since been extended, every effort being made to add to the attractiveness of the beach as a recreation ground. A promenade, which will ultimately extend to Donmouth, is in great part complete; and all the other usual concomitants of a watering-place have been introduced with promising success so far, and likely to be greater in the near future. From Donmouth the northward coast presents little of interest. All the way to the estuary of the Ythan is a region of sand-dunes bound together by marum grass and stunted whins, excellent for golf courses, but lacking in variety. In the sandy mounds in the vicinity of the Ythan have been found many flint chippings and amongst them leaf-shaped flint arrow-heads, chisels and cores, as well as the water-worn stones on which these implements were fashioned. These records of primitive man as he was in the later Stone Age are conspicuous here, and are [Illustration: Girdleness Lighthouse] to be seen in other parts of the county. In the rabbit burrows, which are abundant in the dunes, the stock-dove rears her young. In 1888 a migratory flock of sand-grouse took possession of the dunes, and remained for one season.