A synthetic large pore crystalline metalsilicate zeolite composition, designated as ECR-35, having the formula, expressed in term of mole ratio of oxides: ##STR1## where T is an organic cation selected from the group consisting of tetraethylammonium and methyltriethyl ammonium, and mixtures thereof and X is Al or Ga; wherein the composition consists of an X-ray diffraction pattern having the line intensities:______________________________________ Line # d(.ANG.) Intensity ______________________________________ (1) 15.00 .+-. 0.2 weak to very strong (2) 14.20 .+-. 0.2 very strong (3) 13.40 .+-. 0.2 weak to medium (4) 8.70 .+-. 0.2 medium (5) 8.03 .+-. 0.2 zero to medium (6) 7.40 .+-. 0.15 medium (7) 5.65 .+-. 0.15 medium-strong ______________________________________ and wherein the intensity of line (2) is greater than line (1) which is substantially greater than the intensity of line (3); and wherein the intensity of line (4) is substantially greater than the intensity of line (6) which is greater than the intensity of line (5) and a method for preparing same.