Istria is a triangle about 60 miles long with a maximum breadth of 46 miles. It rises from the southwestern coast gradually up to the Dinaric Alps. Owing to its undulating surface and the absence of coastal plains, it may be regarded as a part of this range, jutting out into the sea. On the whole, Istria may be called a Karst land, for three-fourths of its surface consists of Karst-forming limestone and only one-fourth of sandstone and marl. With few exceptions its natural waterways are confined to the sandstone districts. The peninsula is also a transition region between the mild Mediterranean and central European climates. The summers are dry and in autumn heavy rains fall. Almost all the land is productive and 67 per cent of its population live by agriculture and forestry. Settlement by Slavs of the hills dominating the Adriatic appears to have taken place continuously from the ninth to the seventeenth century. Feudatory chiefs of medieval ages first resorted to this method of developing the uncultivated slopes and highlands of the eastern coast. The Venetian republic and the Austrian government adopted similar measures of colonization. Slavic tribes, hard pressed by their kinsmen or by Tatars from the east, thus found refuge in the mountainous Dalmatian coastland under the ægis of western nations. A traveler taking ship today and sailing from harbor to harbor along the shores of the eastern Adriatic would readily notice the numerical superiority of these descendants of Slavs. They constitute the mass of toilers in every walk of life, and sooner or later probably will erect a political fabric on the foundations of their linguistic preponderance. Slavic dialects are found in the Friulian sections of eastern Italy as well as in the Abruzzi and Molise regions. The Slavic population of Friuli was estimated in 1851 at 26,676. The census of 1901 records the existence of 5,734 Slavic-speaking families scattered in 16 communi and consisting of about 36,000 individuals. The Slavs of Italy may be divided into four dialectical groups as follows:[67] Natisone group composed of 17,291 individuals Torre “ “ “ 12,986 “ Judrio “ “ “ 1,230 “ Resia “ “ “ 4,671 “ The Molise group is the remnant of a once extensive Slav colony which had reached the province of Chieti. Round-headedness, accompanied by high stature and blondness, among inhabitants of the communes of Vasto, Cupello, Monteoderisio, Abbateggio, Lanciano, San Giovanni Teatino, Cascanditella and San Vito Chietino betrays Slavic ancestry. And yet Slavic dialects are hardly heard any longer in these country districts. The communes of Acquaviva Collecroce and San Felice Slavo alone boast of some 4,500 inhabitants who speak Slovene.