Our readers are doubtless aware that cochineal, so extensively used in this country for dying,[1] is a beautiful insect abundantly found in various parts of Mexico and Peru. Some of these insects have lately been sent over to Old Spain, and are doing remarkably well on the prickly pear of that country; indeed, they are said to rival even those of Mexico in the quality and brilliancy of their dye. Their naturalization may doubtless be extended along the shores of the Mediterranean, Sicily, and the different states of Greece. The prickly pear is indigenous in those places, and by little cultivation will afford sufficient nourishment for the cochineal insects. We are also assured, (says an intelligent correspondent of _The Times_,) that these precious insects were introduced last year on the island of Malta, by Dr. Gorman, on account of the government, and that they are likely to do well on that island. Dr. Gorman discovered a few weeks since, in the botanic garden at Cambridge, the _grona sylvestris_, or wild species of cochineal, living among the leaves of the coffee-plants, the acacia, &c. This is the kermes, or gronilla of Spain, about which so much has been said in endeavouring to identify it with the grona fina. At all events, this is the same species as the gronilla found on the hairs of the green oaks in Andalusia; and in some years large and valuable crops of the gronilla are gathered in that part of Spain by the peasantry, and sold to the Moors to dye their scarlet. The gardener at Cambridge could not inform Dr. Gorman how long the insects had been there, or from whence they came, but they went there by the appellation of "amelca bug." The gardener found these insects very destructive to plants upon which they fostered, and although he tried every means short of injuring the plants to remove them, he found it impossible, as they adhere to the leaves and parts of the stem with such tenacity, and are so prolific, that the young ones are often found spreading themselves over the neighbouring plants. On this account, it would be worth while to attempt the cultivation of the prickly pear in the open air in this country, and place the insects upon them, for in all probability the insects would, by good management, do well. [1] It is computed that there have been imported into Europe no less a quantity than 880,000 lbs. weight of cochineal in one year! * * * * * _Fossil Turtle._ The remains of a sea turtle have lately been discovered, and are now in the possession of Mr. Deck, of Cambridge. It is imbedded in a mass of septaria, weighing upwards of 150 pounds, with two fine specimens of fossil wood; and was obtained in digging for cement stone, about five miles from Harwich, in three fathoms water, where, as a mass of stone, it had been used for some time as a stepping block.--_Bakewell's Geology._ * * * * * _Geological Changes._