Geological Chronicle
Montes Jura forms a semi-circular ring of mountains spanning 420.8 kilometers in diameter along the northwestern edge of Mare Imbrium. The range rises to approximately 3,800 meters above the level of Sinus Iridum, the flooded bay it encloses. In the distant past, the range formed the outer wall of a crater about 260 kilometers across before its southeastern face was removed and the interior was flooded with basaltic lava.
The mountain range terminates in two distinct features: the blunt, east-facing cape of Promontorium Heraclides at the southwest and the wedge-shaped Promontorium Laplace to the northeast. Across the north-northwestern curve lies the crater Bianchini, flanked to the west by Sharp and to the northeast by the ruined crater Maupertuis. As the lunar terminator advances two to three nights after the first quarter moon, sunlight catches the mountain peaks to create a line of bright points called the 'jeweled scimitar' effect. Ten to eleven days after a new moon, when the waxing crater rim is illuminated while Sinus Iridum remains in shadow, observers see the illusion of a handle known as the Golden Handle.
Montes Jura was named after the Jura Mountains in eastern France and western Switzerland. Observer Peter Grego described a figurine of 'The Moon Maiden' in the region, discerning her facial profile in Promontorium Heraclides, her hair in the western hills, and her body along Montes Jura. On the side facing Mare Imbrium, the range ends in nearly level plains, while the opposite side merges into a region of rough and irregular terrain