The island of Mallorca, and the Balearic Islands in general, were probably formed some 400 to 300 million years ago. Allow me to quote from the Encyclopedia Britannica, 1911 edition (yes, 1911):
The strata which form the Balearic Isles fall naturally into two divisions. There is an older series, ranging from the Devonian to the Cretaceous, which is folded and faulted and forms all the higher hills, and there is a newer series of Tertiary age, which lies nearly horizontal and rests unconformably upon the older beds. The direction of the folds in the older series is in Iviza nearly west to east, in Majorca south-west to north-east, and in Minorca south to north, thus forming an arc convex towards the south-east. The Devonian is visible only in Minorca, the Trias being the oldest system represented in the other islands. The higher part of the Cretaceous is absent, and it appears to have been during this period that the principal folding of the older beds took place. The Eocene beds are nummulitic. There is a lacustrine group which has usually been placed in the Lower Eocene, but the discovery of Anthracotherium magnum in the interbedded lignites proves it to be Oligocene, in part at least. The Miocene included a limestone with Clypeaster. Pliocene beds also occur.
Mallorca’s Serra de Tramuntana was formed during the Triassic period (250 to 200 million years ago), whilst the Jurassic period in Mallorca lasted from about 200 million to 150 million years ago. If you keep your eyes open, you’ll be able to find prehistoric evidence in the form of fossils just about everywhere. Ammonites were abundant, such as the one shown in my photo, possibly one of the Phylloceratidae family, or is it a Polyplectus discoides?
If you want to find out more about ammonites, fossils and other testimonials of the Jurassic period in Mallorca, you could either consult the Internet, have recourse to a competent book or simply visit the Museu Balear de Ciències Naturals in Sóller. The museum is open Tuesday to Saturday from 10h00 to 18h00 and Sundays from 10h00 to 14h00. The last time I went there, admission fees were 5 €.
The photo was taken in Felanitx, Mallorca, Baleares, Spain. The date: April 17th, 2011. The time was 12:32:05. The location was in Carrer Major, laterally adjoining the Església Parroquial de Sant Miquel. The fossil is about 20 x 30 cm in size.