Would this works ?

public static unsafe IntPtr FindPattern(IntPtr StartAddress, int Length, byte[] Pattern, string Mask)
        {
            MenuForm.Console.Items.Add("Create Allocated Array");
            byte[] Dump = new byte[Length];

            //Create a Dump of the process
            MenuForm.Console.Items.Add("Dumping Process");
            for (int i = 0; i < Length; i++)
            {
                Dump[i] = *(byte*)(StartAddress + i);
            }

            MenuForm.Console.Items.Add("Scanning Pattern");
            //Scan for the pattern
            for (int i = 0; i < Length - Pattern.Length; i++)
            {
                bool Found = true;
                for (int k = 0; k < Pattern.Length; k++)
                {
                    Found = Found & (Dump[i + k] == Pattern[k]) && (Mask[k] == 'x');
                }
                if (Found)
                {
                    Dump = new byte[0]; //Free Up the Dump Memory
                    return (IntPtr)i; //Return the specified Address
                }
            }
            Dump = new byte[0]; //Free Up the Dump Memory
            return (IntPtr)0; //Pattern not found, return 0
            MenuForm.Console.Items.Add("Done");
        }

PatternScanner.FindPattern(MainClass.CShell, 0xFFFFFF, new byte[] { 0x8B, 0x4F, 0x04, 0xA1, 0x00, 0x00, 0x00, 0x00, 0x85, 0xC0, 0x8B, 0x51, 0x04, 0x8B, 0x6A, 0x04 }, "xxxx????xxxxxxxx");