Adairsville on May 17 and more general fighting on Johnston's Cassville line May 18–19. Johnston planned to defeat part of Sherman's force as it approached on multiple routes, but Hood became uncharacteristically cautious and feared encirclement, failing to attack as ordered. Encouraged by Hood and Polk, Johnston ordered another withdrawal, this time across the Etowah River. Johnston's army took up defensive positions at Allatoona Pass south of Cartersville, but Sherman once again turned Johnston's left as he temporarily abandoned his railroad supply line and advanced on Dallas. Johnston was forced to move from his strong position and meet Sherman's army in the open. Fierce but inconclusive fighting occurred on May 25 at New Hope Church, May 27 at Pickett's Mill, and May 28 at Dallas. By June 1, heavy rains turned the roads to quagmires and Sherman was forced to return to the railroad to supply his men. Johnston's new line (called the Brushy Mountain Line) was established by June 4 northwest of Marietta, along Lost Mountain, Pine Mountain, and Brush Mountain. On June 14, following eleven days of steady rain, Sherman was ready to move again. While on a personal reconnaissance, he spotted a group of Confederate officers on Pine Mountain and ordered one of his artillery batteries to open fire. Lt. Gen. Leonidas Polk, the "Fighting Bishop," was killed and Johnston withdrew his men from Pine Mountain, establishing a new line in an arc-shaped defensive position from Kennesaw Mountain to Little Kennesaw Mountain. Hood's corps attempted an unsuccessful attack at Peter Kolb's farm (the Battle of Kolb's Farm) south of Little Kennesaw Mountain on June 22. Maj. Gen. William W. Loring succeeded to temporarily command Polk's corps. Sherman was in a difficult position, stalled north of Atlanta. He could not continue his strategy of moving around Johnston's flank because of the impassable roads, and his railroad supply line was dominated by Johnston's position on the top of Kennesaw Mountain. He reported to Washington "The whole country is one vast fort, and Johnston must have at least of connected trenches with abatis and finished batteries. We gain ground daily, fighting all the time. ... Our lines are now in close contact and the fighting incessant, with a good deal of artillery. As fast as we gain one position the enemy has another all ready. ... Kennesaw ... is the key to the whole country." Sherman decided to break the