Paramount’s “The Firm” emerged as the freshman at the top of the class with a holiday weekend gross estimated by the studio at $ 31.4 million. That meant Universal’s “Jurassic Park” had to go back to its cave with a far-from-undistinguished $ 26 million. Additionally, Buena Vista got $ 9.3 million worth of good news from its reissue of “Snow White and the Seven Dwarfs” and tepid results of $ 7 million from the launch of “Son-in-Law.”Overall Fourth of July business was better than bronto — it was biggest. Early estimates indicate the four-day span will generate a tad less than $ 130 million, which ranks the period as the biggest box office bonanza of all time. It is both the largest gross for four days and, with an estimated $ 105 million, the first instance in history where key films in the marketplace generated more than $ 100 million in a three-day weekend. The only record that may be denied the frame is the all-time weekend gross, which was established in 1989 at $ 131.8 million covering a five-day period. The marketplace registered its first real signs of expansion this summer. Audiences were out in record numbers, providing big returns for a broad spectrum of pictures. Compared with last year, revenues were up a staggering 45% and, for the first time in months, the year to date is running ahead of 1992. The domestic box office of $ 2.33 billion is approximately 4% greater than the comparable figure last year. “The Firm” continued firing on from its Wednesday preem to finish the weekend at $ 31.4 million. However, the studio is estimating extremely soft Monday business and the film could quite easily wind up at around $ 33 million for the sesh. Either way, the results are big, with averages of $ 13,120 from 2,393 prints and a cume of $ 44.5 million. “It’s good news for us and the industry,” said Paramount Motion Picture Group prexy Barry London. “Pictures like this don’t generally open to this level of business. What’s great is that ‘The Firm’ could open so well and the other key pictures in the marketplace continue to play unaffected.” As expected, “Jurassic Park” nosed past $ 200 million on Saturday and finished the weekend with about $ 26 million to rank second. Despite scientific reports to the contrary, these dinosaurs will not die. Off 18% for the frame, the film averaged $ 10,410 from 2,498 playdates. After four weekends it has chomped $ 212.7 million to rank 11th in the all-time money earners list. TriStar’s “Sleepless in Seattle” was bright-eyed in third with $ 17 million. The romantic comedy held extremely well in its second weekend, slipping a mere 14% and looking like an easy $ 100 million champion. Averaging $ 10,620 from 1, 601 encounters brings its cume to $ 45.1 million. Warner Bros.’ “Dennis the Menace” was oblivious to the competition, finishing fourth with $ 10.8 million. It was dead even with its opening weekend with averages of $ 5,180 from 2,085 brat packs. After 11 days, it has a gross of $ 26 .9 million. Buena Vista’s reissue of the 1937 vintage “Snow White” retained its “fairest of them all” status with a fifth-place, $ 9.3 million gross. The company’s first animated feature bit into the apple for averages of $ 5,120 from 1,814 workplaces. The solid opening had Disney exex breathing a sigh of relief for the ongoing viability of the animated franchise. The prognosis for Hollywood Pictures’ “Son-in-Law” was less positive as it entered in sixth spot with $ 7 million. The Pauly Shore comedy did steady business but failed to build its audience as the weekend progressed. It averaged $ 5,040 from 1,389 parlors in its debut. Columbia’s “Last Action Hero” finished seventh with $ 6.4 million, according to the studio. Other trackers had the film about $ 1 million southward, but regardless, its 29% reported drop was the most severe for the frame. Averaging 2 ,770 from 2,306 bijous brings its cume to $ 40.1 million. Columbia, however, is shifting into high gear on next weekend’s launch of the Clint Eastwood starrer “In the Line of Fire.” The Castle Rock production sneaked Saturday in 573 venues to outstanding response. The studio was estimating 85% capacity on the peeks with 95% favorable response in the top two categories. Touchstone’s “What’s Love Got to Do With It” was showing strong legs with eighth place and a $ 5.8 million gross. The rockin’ musical bio socked out averages of $ 5,270 from 1,100 gigs. Off a slim 5%, it has a cume of $ 21.7 million. TriStar’s “Cliffhanger” held on for $ 3.8 million and ninth position. The pliant actioner edged down 16% with averages of $ 2,130 from 1,786 playdates. To date it’s earned $ 71.3 million. In 10th with an estimated $ 1.8 million was New Line’s “Menace II Society.” The urban drama was toughing it out with averages of $ 3,250 from 553 encounters. Down 10% for the frame, its cume is $ 21 million.